CINXE.COM

<!DOCTYPE html> <html class="client-nojs vector-feature-language-in-header-enabled vector-feature-language-in-main-page-header-disabled vector-feature-sticky-header-disabled vector-feature-page-tools-pinned-disabled vector-feature-toc-pinned-clientpref-1 vector-feature-main-menu-pinned-disabled vector-feature-limited-width-clientpref-1 vector-feature-limited-width-content-disabled vector-feature-custom-font-size-clientpref-1 vector-feature-appearance-pinned-clientpref-1 vector-feature-night-mode-enabled skin-theme-clientpref-day vector-toc-available" lang="en" dir="ltr"> <head> <meta charset="UTF-8"> <title>Mental calculator: Difference between revisions - Wikipedia</title> <script>(function(){var className="client-js vector-feature-language-in-header-enabled vector-feature-language-in-main-page-header-disabled vector-feature-sticky-header-disabled vector-feature-page-tools-pinned-disabled vector-feature-toc-pinned-clientpref-1 vector-feature-main-menu-pinned-disabled vector-feature-limited-width-clientpref-1 vector-feature-limited-width-content-disabled vector-feature-custom-font-size-clientpref-1 vector-feature-appearance-pinned-clientpref-1 vector-feature-night-mode-enabled skin-theme-clientpref-day vector-toc-available";var cookie=document.cookie.match(/(?:^|; )enwikimwclientpreferences=([^;]+)/);if(cookie){cookie[1].split('%2C').forEach(function(pref){className=className.replace(new RegExp('(^| )'+pref.replace(/-clientpref-\w+$|[^\w-]+/g,'')+'-clientpref-\\w+( |$)'),'$1'+pref+'$2');});}document.documentElement.className=className;}());RLCONF={"wgBreakFrames":false,"wgSeparatorTransformTable":["",""],"wgDigitTransformTable":["",""],"wgDefaultDateFormat":"dmy" ,"wgMonthNames":["","January","February","March","April","May","June","July","August","September","October","November","December"],"wgRequestId":"e37252c1-f6ad-4392-ae13-56ca76e767aa","wgCanonicalNamespace":"","wgCanonicalSpecialPageName":false,"wgNamespaceNumber":0,"wgPageName":"Mental_calculator","wgTitle":"Mental calculator","wgCurRevisionId":1259467834,"wgRevisionId":1238777068,"wgArticleId":455386,"wgIsArticle":true,"wgIsRedirect":false,"wgAction":"view","wgUserName":null,"wgUserGroups":["*"],"wgCategories":["Articles with short description","Short description is different from Wikidata","Articles lacking in-text citations from August 2011","All articles lacking in-text citations","Mental calculators","Giftedness"],"wgPageViewLanguage":"en","wgPageContentLanguage":"en","wgPageContentModel":"wikitext","wgRelevantPageName":"Mental_calculator","wgRelevantArticleId":455386,"wgIsProbablyEditable":true,"wgRelevantPageIsProbablyEditable":true,"wgRestrictionEdit":[],"wgRestrictionMove":[] ,"wgNoticeProject":"wikipedia","wgCiteReferencePreviewsActive":false,"wgFlaggedRevsParams":{"tags":{"status":{"levels":1}}},"wgMediaViewerOnClick":true,"wgMediaViewerEnabledByDefault":true,"wgPopupsFlags":0,"wgVisualEditor":{"pageLanguageCode":"en","pageLanguageDir":"ltr","pageVariantFallbacks":"en"},"wgMFDisplayWikibaseDescriptions":{"search":true,"watchlist":true,"tagline":false,"nearby":true},"wgWMESchemaEditAttemptStepOversample":false,"wgWMEPageLength":10000,"extRevisionSliderTimeOffset":0,"wgDiffOldId":1237480976,"wgDiffNewId":1238777068,"wgRelatedArticlesCompat":[],"wgCentralAuthMobileDomain":false,"wgEditSubmitButtonLabelPublish":true,"wgULSPosition":"interlanguage","wgULSisCompactLinksEnabled":false,"wgVector2022LanguageInHeader":true,"wgULSisLanguageSelectorEmpty":false,"wgWikibaseItemId":"Q372646","wgCheckUserClientHintsHeadersJsApi":["brands","architecture","bitness","fullVersionList","mobile","model","platform","platformVersion"],"GEHomepageSuggestedEditsEnableTopics":true ,"wgGETopicsMatchModeEnabled":false,"wgGEStructuredTaskRejectionReasonTextInputEnabled":false,"wgGELevelingUpEnabledForUser":false};RLSTATE={"ext.globalCssJs.user.styles":"ready","site.styles":"ready","user.styles":"ready","ext.globalCssJs.user":"ready","user":"ready","user.options":"loading","ext.visualEditor.diffPage.init.styles":"ready","oojs-ui.styles.icons-accessibility":"ready","oojs-ui.styles.icons-editing-advanced":"ready","oojs-ui-core.styles":"ready","oojs-ui.styles.indicators":"ready","mediawiki.widgets.styles":"ready","oojs-ui-core.icons":"ready","ext.RevisionSlider.lazyCss":"ready","mediawiki.interface.helpers.styles":"ready","mediawiki.diff.styles":"ready","ext.cite.styles":"ready","mediawiki.helplink":"ready","skins.vector.search.codex.styles":"ready","skins.vector.styles":"ready","skins.vector.icons":"ready","ext.wikimediamessages.styles":"ready","ext.visualEditor.desktopArticleTarget.noscript":"ready","ext.uls.interlanguage":"ready","wikibase.client.init":"ready", "ext.wikimediaBadges":"ready"};RLPAGEMODULES=["ext.visualEditor.diffPage.init","ext.RevisionSlider.lazyJs","mediawiki.diff","ext.cite.ux-enhancements","mediawiki.page.media","site","mediawiki.page.ready","mediawiki.toc","skins.vector.js","ext.centralNotice.geoIP","ext.gadget.ReferenceTooltips","ext.gadget.switcher","ext.urlShortener.toolbar","ext.centralauth.centralautologin","mmv.bootstrap","ext.popups","ext.visualEditor.desktopArticleTarget.init","ext.visualEditor.targetLoader","ext.echo.centralauth","ext.eventLogging","ext.wikimediaEvents","ext.navigationTiming","ext.uls.interface","ext.cx.eventlogging.campaigns","ext.cx.uls.quick.actions","wikibase.client.vector-2022","ext.checkUser.clientHints","ext.quicksurveys.init","ext.growthExperiments.SuggestedEditSession","wikibase.sidebar.tracking"];</script> <script>(RLQ=window.RLQ||[]).push(function(){mw.loader.impl(function(){return["user.options@12s5i",function($,jQuery,require,module){mw.user.tokens.set({"patrolToken":"+\\","watchToken":"+\\","csrfToken":"+\\"}); }];});});</script> <link rel="stylesheet" href="/w/load.php?lang=en&modules=ext.RevisionSlider.lazyCss%7Cext.cite.styles%7Cext.uls.interlanguage%7Cext.visualEditor.desktopArticleTarget.noscript%7Cext.visualEditor.diffPage.init.styles%7Cext.wikimediaBadges%7Cext.wikimediamessages.styles%7Cmediawiki.diff.styles%7Cmediawiki.helplink%7Cmediawiki.interface.helpers.styles%7Cmediawiki.widgets.styles%7Coojs-ui-core.icons%2Cstyles%7Coojs-ui.styles.icons-accessibility%2Cicons-editing-advanced%2Cindicators%7Cskins.vector.icons%2Cstyles%7Cskins.vector.search.codex.styles%7Cwikibase.client.init&only=styles&skin=vector-2022"> <script async="" src="/w/load.php?lang=en&modules=startup&only=scripts&raw=1&skin=vector-2022"></script> <meta name="ResourceLoaderDynamicStyles" content=""> <link rel="stylesheet" href="/w/load.php?lang=en&modules=site.styles&only=styles&skin=vector-2022"> <meta name="generator" content="MediaWiki 1.44.0-wmf.4"> <meta name="referrer" content="origin"> <meta name="referrer" content="origin-when-cross-origin"> <meta name="robots" content="noindex,nofollow,max-image-preview:standard"> <meta name="format-detection" content="telephone=no"> <meta property="og:image" content="https://upload.wikimedia.org/wikipedia/commons/thumb/d/d7/Leonhard_Euler.jpg/1200px-Leonhard_Euler.jpg"> <meta property="og:image:width" content="1200"> <meta property="og:image:height" content="1551"> <meta property="og:image" content="https://upload.wikimedia.org/wikipedia/commons/thumb/d/d7/Leonhard_Euler.jpg/800px-Leonhard_Euler.jpg"> <meta property="og:image:width" content="800"> <meta property="og:image:height" content="1034"> <meta property="og:image" content="https://upload.wikimedia.org/wikipedia/commons/thumb/d/d7/Leonhard_Euler.jpg/640px-Leonhard_Euler.jpg"> <meta property="og:image:width" content="640"> <meta property="og:image:height" content="827"> <meta name="viewport" content="width=1120"> <meta property="og:title" content="Mental calculator: Difference between revisions - Wikipedia"> <meta property="og:type" content="website"> <link rel="preconnect" href="//upload.wikimedia.org"> <link rel="alternate" media="only screen and (max-width: 640px)" href="//en.m.wikipedia.org/wiki/Mental_calculator"> <link rel="alternate" type="application/x-wiki" title="Edit this page" href="/w/index.php?title=Mental_calculator&action=edit"> <link rel="apple-touch-icon" href="/static/apple-touch/wikipedia.png"> <link rel="icon" href="/static/favicon/wikipedia.ico"> <link rel="search" type="application/opensearchdescription+xml" href="/w/rest.php/v1/search" title="Wikipedia (en)"> <link rel="EditURI" type="application/rsd+xml" href="//en.wikipedia.org/w/api.php?action=rsd"> <link rel="canonical" href="https://en.wikipedia.org/wiki/Mental_calculator"> <link rel="license" href="https://creativecommons.org/licenses/by-sa/4.0/deed.en"> <link rel="alternate" type="application/atom+xml" title="Wikipedia Atom feed" href="/w/index.php?title=Special:RecentChanges&feed=atom"> <link rel="dns-prefetch" href="//login.wikimedia.org"> </head> <body class="mw-article-diff skin--responsive skin-vector skin-vector-search-vue mediawiki ltr sitedir-ltr mw-hide-empty-elt ns-0 ns-subject mw-editable page-Mental_calculator rootpage-Mental_calculator skin-vector-2022 action-view"><a class="mw-jump-link" href="#bodyContent">Jump to content</a> <div class="vector-header-container"> <header class="vector-header mw-header"> <div class="vector-header-start"> <nav class="vector-main-menu-landmark" aria-label="Site"> <div id="vector-main-menu-dropdown" class="vector-dropdown vector-main-menu-dropdown vector-button-flush-left vector-button-flush-right" > <input type="checkbox" id="vector-main-menu-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-main-menu-dropdown" class="vector-dropdown-checkbox " aria-label="Main menu" > <label id="vector-main-menu-dropdown-label" for="vector-main-menu-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-menu mw-ui-icon-wikimedia-menu"></span> <span class="vector-dropdown-label-text">Main menu</span> </label> <div class="vector-dropdown-content"> <div id="vector-main-menu-unpinned-container" class="vector-unpinned-container"> <div id="vector-main-menu" class="vector-main-menu vector-pinnable-element"> <div class="vector-pinnable-header vector-main-menu-pinnable-header vector-pinnable-header-unpinned" data-feature-name="main-menu-pinned" data-pinnable-element-id="vector-main-menu" data-pinned-container-id="vector-main-menu-pinned-container" data-unpinned-container-id="vector-main-menu-unpinned-container" > <div class="vector-pinnable-header-label">Main menu</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-main-menu.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-main-menu.unpin">hide</button> </div> <div id="p-navigation" class="vector-menu mw-portlet mw-portlet-navigation" > <div class="vector-menu-heading"> Navigation </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="n-mainpage-description" class="mw-list-item"><a href="/wiki/Main_Page" title="Visit the main page [z]" accesskey="z"><span>Main page</span></a></li><li id="n-contents" class="mw-list-item"><a href="/wiki/Wikipedia:Contents" title="Guides to browsing Wikipedia"><span>Contents</span></a></li><li id="n-currentevents" class="mw-list-item"><a href="/wiki/Portal:Current_events" title="Articles related to current events"><span>Current events</span></a></li><li id="n-randompage" class="mw-list-item"><a href="/wiki/Special:Random" title="Visit a randomly selected article [x]" accesskey="x"><span>Random article</span></a></li><li id="n-aboutsite" class="mw-list-item"><a href="/wiki/Wikipedia:About" title="Learn about Wikipedia and how it works"><span>About Wikipedia</span></a></li><li id="n-contactpage" class="mw-list-item"><a href="//en.wikipedia.org/wiki/Wikipedia:Contact_us" title="How to contact Wikipedia"><span>Contact us</span></a></li> </ul> </div> </div> <div id="p-interaction" class="vector-menu mw-portlet mw-portlet-interaction" > <div class="vector-menu-heading"> Contribute </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="n-help" class="mw-list-item"><a href="/wiki/Help:Contents" title="Guidance on how to use and edit Wikipedia"><span>Help</span></a></li><li id="n-introduction" class="mw-list-item"><a href="/wiki/Help:Introduction" title="Learn how to edit Wikipedia"><span>Learn to edit</span></a></li><li id="n-portal" class="mw-list-item"><a href="/wiki/Wikipedia:Community_portal" title="The hub for editors"><span>Community portal</span></a></li><li id="n-recentchanges" class="mw-list-item"><a href="/wiki/Special:RecentChanges" title="A list of recent changes to Wikipedia [r]" accesskey="r"><span>Recent changes</span></a></li><li id="n-upload" class="mw-list-item"><a href="/wiki/Wikipedia:File_upload_wizard" title="Add images or other media for use on Wikipedia"><span>Upload file</span></a></li> </ul> </div> </div> </div> </div> </div> </div> </nav> <a href="/wiki/Main_Page" class="mw-logo"> <img class="mw-logo-icon" src="/static/images/icons/wikipedia.png" alt="" aria-hidden="true" height="50" width="50"> <span class="mw-logo-container skin-invert"> <img class="mw-logo-wordmark" alt="Wikipedia" src="/static/images/mobile/copyright/wikipedia-wordmark-en.svg" style="width: 7.5em; height: 1.125em;"> <img class="mw-logo-tagline" alt="The Free Encyclopedia" src="/static/images/mobile/copyright/wikipedia-tagline-en.svg" width="117" height="13" style="width: 7.3125em; height: 0.8125em;"> </span> </a> </div> <div class="vector-header-end"> <div id="p-search" role="search" class="vector-search-box-vue vector-search-box-collapses vector-search-box-show-thumbnail vector-search-box-auto-expand-width vector-search-box"> <a href="/wiki/Special:Search" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only search-toggle" title="Search Wikipedia [f]" accesskey="f"><span class="vector-icon mw-ui-icon-search mw-ui-icon-wikimedia-search"></span> <span>Search</span> </a> <div class="vector-typeahead-search-container"> <div class="cdx-typeahead-search cdx-typeahead-search--show-thumbnail cdx-typeahead-search--auto-expand-width"> <form action="/w/index.php" id="searchform" class="cdx-search-input cdx-search-input--has-end-button"> <div id="simpleSearch" class="cdx-search-input__input-wrapper" data-search-loc="header-moved"> <div class="cdx-text-input cdx-text-input--has-start-icon"> <input class="cdx-text-input__input" type="search" name="search" placeholder="Search Wikipedia" aria-label="Search Wikipedia" autocapitalize="sentences" title="Search Wikipedia [f]" accesskey="f" id="searchInput" > <span class="cdx-text-input__icon cdx-text-input__start-icon"></span> </div> <input type="hidden" name="title" value="Special:Search"> </div> <button class="cdx-button cdx-search-input__end-button">Search</button> </form> </div> </div> </div> <nav class="vector-user-links vector-user-links-wide" aria-label="Personal tools"> <div class="vector-user-links-main"> <div id="p-vector-user-menu-preferences" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <div id="p-vector-user-menu-userpage" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <nav class="vector-appearance-landmark" aria-label="Appearance"> <div id="vector-appearance-dropdown" class="vector-dropdown " title="Change the appearance of the page's font size, width, and color" > <input type="checkbox" id="vector-appearance-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-appearance-dropdown" class="vector-dropdown-checkbox " aria-label="Appearance" > <label id="vector-appearance-dropdown-label" for="vector-appearance-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-appearance mw-ui-icon-wikimedia-appearance"></span> <span class="vector-dropdown-label-text">Appearance</span> </label> <div class="vector-dropdown-content"> <div id="vector-appearance-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <div id="p-vector-user-menu-notifications" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <div id="p-vector-user-menu-overflow" class="vector-menu mw-portlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-sitesupport-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="https://donate.wikimedia.org/wiki/Special:FundraiserRedirector?utm_source=donate&utm_medium=sidebar&utm_campaign=C13_en.wikipedia.org&uselang=en" class=""><span>Donate</span></a> </li> <li id="pt-createaccount-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="/w/index.php?title=Special:CreateAccount&returnto=Mental+calculator&returntoquery=diff%3D1238777068" title="You are encouraged to create an account and log in; however, it is not mandatory" class=""><span>Create account</span></a> </li> <li id="pt-login-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="/w/index.php?title=Special:UserLogin&returnto=Mental+calculator&returntoquery=diff%3D1238777068" title="You're encouraged to log in; however, it's not mandatory. [o]" accesskey="o" class=""><span>Log in</span></a> </li> </ul> </div> </div> </div> <div id="vector-user-links-dropdown" class="vector-dropdown vector-user-menu vector-button-flush-right vector-user-menu-logged-out" title="Log in and more options" > <input type="checkbox" id="vector-user-links-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-user-links-dropdown" class="vector-dropdown-checkbox " aria-label="Personal tools" > <label id="vector-user-links-dropdown-label" for="vector-user-links-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-ellipsis mw-ui-icon-wikimedia-ellipsis"></span> <span class="vector-dropdown-label-text">Personal tools</span> </label> <div class="vector-dropdown-content"> <div id="p-personal" class="vector-menu mw-portlet mw-portlet-personal user-links-collapsible-item" title="User menu" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-sitesupport" class="user-links-collapsible-item mw-list-item"><a href="https://donate.wikimedia.org/wiki/Special:FundraiserRedirector?utm_source=donate&utm_medium=sidebar&utm_campaign=C13_en.wikipedia.org&uselang=en"><span>Donate</span></a></li><li id="pt-createaccount" class="user-links-collapsible-item mw-list-item"><a href="/w/index.php?title=Special:CreateAccount&returnto=Mental+calculator&returntoquery=diff%3D1238777068" title="You are encouraged to create an account and log in; however, it is not mandatory"><span class="vector-icon mw-ui-icon-userAdd mw-ui-icon-wikimedia-userAdd"></span> <span>Create account</span></a></li><li id="pt-login" class="user-links-collapsible-item mw-list-item"><a href="/w/index.php?title=Special:UserLogin&returnto=Mental+calculator&returntoquery=diff%3D1238777068" title="You're encouraged to log in; however, it's not mandatory. [o]" accesskey="o"><span class="vector-icon mw-ui-icon-logIn mw-ui-icon-wikimedia-logIn"></span> <span>Log in</span></a></li> </ul> </div> </div> <div id="p-user-menu-anon-editor" class="vector-menu mw-portlet mw-portlet-user-menu-anon-editor" > <div class="vector-menu-heading"> Pages for logged out editors <a href="/wiki/Help:Introduction" aria-label="Learn more about editing"><span>learn more</span></a> </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-anoncontribs" class="mw-list-item"><a href="/wiki/Special:MyContributions" title="A list of edits made from this IP address [y]" accesskey="y"><span>Contributions</span></a></li><li id="pt-anontalk" class="mw-list-item"><a href="/wiki/Special:MyTalk" title="Discussion about edits from this IP address [n]" accesskey="n"><span>Talk</span></a></li> </ul> </div> </div> </div> </div> </nav> </div> </header> </div> <div class="mw-page-container"> <div class="mw-page-container-inner"> <div class="vector-sitenotice-container"> <div id="siteNotice"></div> </div> <div class="vector-column-start"> <div class="vector-main-menu-container"> <div id="mw-navigation"> <nav id="mw-panel" class="vector-main-menu-landmark" aria-label="Site"> <div id="vector-main-menu-pinned-container" class="vector-pinned-container"> </div> </nav> </div> </div> <div class="vector-sticky-pinned-container"> <nav id="mw-panel-toc" aria-label="Contents" data-event-name="ui.sidebar-toc" class="mw-table-of-contents-container vector-toc-landmark"> <div id="vector-toc-pinned-container" class="vector-pinned-container"> <div id="vector-toc" class="vector-toc vector-pinnable-element"> <div class="vector-pinnable-header vector-toc-pinnable-header vector-pinnable-header-pinned" data-feature-name="toc-pinned" data-pinnable-element-id="vector-toc" > <h2 class="vector-pinnable-header-label">Contents</h2> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-toc.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-toc.unpin">hide</button> </div> <ul class="vector-toc-contents" id="mw-panel-toc-list"> <li id="toc-mw-content-text" class="vector-toc-list-item vector-toc-level-1"> <a href="#" class="vector-toc-link"> <div class="vector-toc-text">(Top)</div> </a> </li> <li id="toc-Champion_mental_calculators" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Champion_mental_calculators"> <div class="vector-toc-text"> <span class="vector-toc-numb">1</span> <span>Champion mental calculators</span> </div> </a> <ul id="toc-Champion_mental_calculators-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Mental_calculators_in_fiction" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Mental_calculators_in_fiction"> <div class="vector-toc-text"> <span class="vector-toc-numb">2</span> <span>Mental calculators in fiction</span> </div> </a> <button aria-controls="toc-Mental_calculators_in_fiction-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Mental calculators in fiction subsection</span> </button> <ul id="toc-Mental_calculators_in_fiction-sublist" class="vector-toc-list"> <li id="toc-Dune" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Dune"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.1</span> <span>Dune</span> </div> </a> <ul id="toc-Dune-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Matilda" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Matilda"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.2</span> <span>Matilda</span> </div> </a> <ul id="toc-Matilda-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Other" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Other"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.3</span> <span>Other</span> </div> </a> <ul id="toc-Other-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-See_also" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#See_also"> <div class="vector-toc-text"> <span class="vector-toc-numb">3</span> <span>See also</span> </div> </a> <ul id="toc-See_also-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-References" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#References"> <div class="vector-toc-text"> <span class="vector-toc-numb">4</span> <span>References</span> </div> </a> <ul id="toc-References-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Further_reading" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Further_reading"> <div class="vector-toc-text"> <span class="vector-toc-numb">5</span> <span>Further reading</span> </div> </a> <ul id="toc-Further_reading-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-External_links" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#External_links"> <div class="vector-toc-text"> <span class="vector-toc-numb">6</span> <span>External links</span> </div> </a> <ul id="toc-External_links-sublist" class="vector-toc-list"> </ul> </li> </ul> </div> </div> </nav> </div> </div> <div class="mw-content-container"> <main id="content" class="mw-body"> <header class="mw-body-header vector-page-titlebar"> <nav aria-label="Contents" class="vector-toc-landmark"> <div id="vector-page-titlebar-toc" class="vector-dropdown vector-page-titlebar-toc vector-button-flush-left" > <input type="checkbox" id="vector-page-titlebar-toc-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-titlebar-toc" class="vector-dropdown-checkbox " aria-label="Toggle the table of contents" > <label id="vector-page-titlebar-toc-label" for="vector-page-titlebar-toc-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-listBullet mw-ui-icon-wikimedia-listBullet"></span> <span class="vector-dropdown-label-text">Toggle the table of contents</span> </label> <div class="vector-dropdown-content"> <div id="vector-page-titlebar-toc-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <h1 id="firstHeading" class="firstHeading mw-first-heading">Mental calculator: Difference between revisions</h1> <div id="p-lang-btn" class="vector-dropdown mw-portlet mw-portlet-lang" > <input type="checkbox" id="p-lang-btn-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-p-lang-btn" class="vector-dropdown-checkbox mw-interlanguage-selector" aria-label="Go to an article in another language. Available in 11 languages" > <label id="p-lang-btn-label" for="p-lang-btn-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--action-progressive mw-portlet-lang-heading-11" aria-hidden="true" ><span class="vector-icon mw-ui-icon-language-progressive mw-ui-icon-wikimedia-language-progressive"></span> <span class="vector-dropdown-label-text">11 languages</span> </label> <div class="vector-dropdown-content"> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="interlanguage-link interwiki-de mw-list-item"><a href="https://de.wikipedia.org/wiki/Rechenk%C3%BCnstler" title="Rechenkünstler – German" lang="de" hreflang="de" data-title="Rechenkünstler" data-language-autonym="Deutsch" data-language-local-name="German" class="interlanguage-link-target"><span>Deutsch</span></a></li><li class="interlanguage-link interwiki-es mw-list-item"><a href="https://es.wikipedia.org/wiki/Calculista_mental" title="Calculista mental – Spanish" lang="es" hreflang="es" data-title="Calculista mental" data-language-autonym="Español" data-language-local-name="Spanish" class="interlanguage-link-target"><span>Español</span></a></li><li class="interlanguage-link interwiki-fa mw-list-item"><a href="https://fa.wikipedia.org/wiki/%D8%AD%D8%B3%D8%A7%D8%A8%DA%AF%D8%B1_%D8%B0%D9%87%D9%86%DB%8C" title="حسابگر ذهنی – Persian" lang="fa" hreflang="fa" data-title="حسابگر ذهنی" data-language-autonym="فارسی" data-language-local-name="Persian" class="interlanguage-link-target"><span>فارسی</span></a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikipedia.org/wiki/Calculateur_prodige" title="Calculateur prodige – French" lang="fr" hreflang="fr" data-title="Calculateur prodige" data-language-autonym="Français" data-language-local-name="French" class="interlanguage-link-target"><span>Français</span></a></li><li class="interlanguage-link interwiki-it mw-list-item"><a href="https://it.wikipedia.org/wiki/Calcolatore_prodigio" title="Calcolatore prodigio – Italian" lang="it" hreflang="it" data-title="Calcolatore prodigio" data-language-autonym="Italiano" data-language-local-name="Italian" class="interlanguage-link-target"><span>Italiano</span></a></li><li class="interlanguage-link interwiki-he mw-list-item"><a href="https://he.wikipedia.org/wiki/%D7%92%D7%90%D7%95%D7%9F_%D7%97%D7%99%D7%A9%D7%95%D7%91" title="גאון חישוב – Hebrew" lang="he" hreflang="he" data-title="גאון חישוב" data-language-autonym="עברית" data-language-local-name="Hebrew" class="interlanguage-link-target"><span>עברית</span></a></li><li class="interlanguage-link interwiki-hu mw-list-item"><a href="https://hu.wikipedia.org/wiki/Fejsz%C3%A1mol%C3%B3_m%C5%B1v%C3%A9sz" title="Fejszámoló művész – Hungarian" lang="hu" hreflang="hu" data-title="Fejszámoló művész" data-language-autonym="Magyar" data-language-local-name="Hungarian" class="interlanguage-link-target"><span>Magyar</span></a></li><li class="interlanguage-link interwiki-nl mw-list-item"><a href="https://nl.wikipedia.org/wiki/Rekenwonder" title="Rekenwonder – Dutch" lang="nl" hreflang="nl" data-title="Rekenwonder" data-language-autonym="Nederlands" data-language-local-name="Dutch" class="interlanguage-link-target"><span>Nederlands</span></a></li><li class="interlanguage-link interwiki-pt mw-list-item"><a href="https://pt.wikipedia.org/wiki/Calculadora_humana" title="Calculadora humana – Portuguese" lang="pt" hreflang="pt" data-title="Calculadora humana" data-language-autonym="Português" data-language-local-name="Portuguese" class="interlanguage-link-target"><span>Português</span></a></li><li class="interlanguage-link interwiki-ru mw-list-item"><a href="https://ru.wikipedia.org/wiki/%D0%A4%D0%B5%D0%BD%D0%BE%D0%BC%D0%B5%D0%BD%D0%B0%D0%BB%D1%8C%D0%BD%D1%8B%D0%B9_%D1%81%D1%87%D1%91%D1%82%D1%87%D0%B8%D0%BA" title="Феноменальный счётчик – Russian" lang="ru" hreflang="ru" data-title="Феноменальный счётчик" data-language-autonym="Русский" data-language-local-name="Russian" class="interlanguage-link-target"><span>Русский</span></a></li><li class="interlanguage-link interwiki-uk mw-list-item"><a href="https://uk.wikipedia.org/wiki/%D0%9F%D0%BE%D0%B4%D1%83%D0%BC%D0%BA%D0%BE%D0%B2%D0%B8%D0%B9_%D0%BE%D0%B1%D1%87%D0%B8%D1%81%D0%BB%D1%8E%D0%B2%D0%B0%D1%87" title="Подумковий обчислювач – Ukrainian" lang="uk" hreflang="uk" data-title="Подумковий обчислювач" data-language-autonym="Українська" data-language-local-name="Ukrainian" class="interlanguage-link-target"><span>Українська</span></a></li> </ul> <div class="after-portlet after-portlet-lang"><span class="wb-langlinks-edit wb-langlinks-link"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q372646#sitelinks-wikipedia" title="Edit interlanguage links" class="wbc-editpage">Edit links</a></span></div> </div> </div> </div> </header> <div class="vector-page-toolbar"> <div class="vector-page-toolbar-container"> <div id="left-navigation"> <nav aria-label="Namespaces"> <div id="p-associated-pages" class="vector-menu vector-menu-tabs mw-portlet mw-portlet-associated-pages" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-nstab-main" class="selected vector-tab-noicon mw-list-item"><a href="/wiki/Mental_calculator" title="View the content page [c]" accesskey="c"><span>Article</span></a></li><li id="ca-talk" class="vector-tab-noicon mw-list-item"><a href="/wiki/Talk:Mental_calculator" rel="discussion" title="Discuss improvements to the content page [t]" accesskey="t"><span>Talk</span></a></li> </ul> </div> </div> <div id="vector-variants-dropdown" class="vector-dropdown emptyPortlet" > <input type="checkbox" id="vector-variants-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-variants-dropdown" class="vector-dropdown-checkbox " aria-label="Change language variant" > <label id="vector-variants-dropdown-label" for="vector-variants-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet" aria-hidden="true" ><span class="vector-dropdown-label-text">English</span> </label> <div class="vector-dropdown-content"> <div id="p-variants" class="vector-menu mw-portlet mw-portlet-variants emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> </div> </div> </nav> </div> <div id="right-navigation" class="vector-collapsible"> <nav aria-label="Views"> <div id="p-views" class="vector-menu vector-menu-tabs mw-portlet mw-portlet-views" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-view" class="selected vector-tab-noicon mw-list-item"><a href="/wiki/Mental_calculator"><span>Read</span></a></li><li id="ca-edit" class="vector-tab-noicon mw-list-item"><a href="/w/index.php?title=Mental_calculator&action=edit&oldid=1238777068" title="Edit this page [e]" accesskey="e"><span>Edit</span></a></li><li id="ca-history" class="vector-tab-noicon mw-list-item"><a href="/w/index.php?title=Mental_calculator&action=history" title="Past revisions of this page [h]" accesskey="h"><span>View history</span></a></li> </ul> </div> </div> </nav> <nav class="vector-page-tools-landmark" aria-label="Page tools"> <div id="vector-page-tools-dropdown" class="vector-dropdown vector-page-tools-dropdown" > <input type="checkbox" id="vector-page-tools-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-tools-dropdown" class="vector-dropdown-checkbox " aria-label="Tools" > <label id="vector-page-tools-dropdown-label" for="vector-page-tools-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet" aria-hidden="true" ><span class="vector-dropdown-label-text">Tools</span> </label> <div class="vector-dropdown-content"> <div id="vector-page-tools-unpinned-container" class="vector-unpinned-container"> <div id="vector-page-tools" class="vector-page-tools vector-pinnable-element"> <div class="vector-pinnable-header vector-page-tools-pinnable-header vector-pinnable-header-unpinned" data-feature-name="page-tools-pinned" data-pinnable-element-id="vector-page-tools" data-pinned-container-id="vector-page-tools-pinned-container" data-unpinned-container-id="vector-page-tools-unpinned-container" > <div class="vector-pinnable-header-label">Tools</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-page-tools.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-page-tools.unpin">hide</button> </div> <div id="p-cactions" class="vector-menu mw-portlet mw-portlet-cactions emptyPortlet vector-has-collapsible-items" title="More options" > <div class="vector-menu-heading"> Actions </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-more-view" class="selected vector-more-collapsible-item mw-list-item"><a href="/wiki/Mental_calculator"><span>Read</span></a></li><li id="ca-more-edit" class="vector-more-collapsible-item mw-list-item"><a href="/w/index.php?title=Mental_calculator&action=edit&oldid=1238777068" title="Edit this page [e]" accesskey="e"><span>Edit</span></a></li><li id="ca-more-history" class="vector-more-collapsible-item mw-list-item"><a href="/w/index.php?title=Mental_calculator&action=history"><span>View history</span></a></li> </ul> </div> </div> <div id="p-tb" class="vector-menu mw-portlet mw-portlet-tb" > <div class="vector-menu-heading"> General </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="t-whatlinkshere" class="mw-list-item"><a href="/wiki/Special:WhatLinksHere/Mental_calculator" title="List of all English Wikipedia pages containing links to this page [j]" accesskey="j"><span>What links here</span></a></li><li id="t-recentchangeslinked" class="mw-list-item"><a href="/wiki/Special:RecentChangesLinked/Mental_calculator" rel="nofollow" title="Recent changes in pages linked from this page [k]" accesskey="k"><span>Related changes</span></a></li><li id="t-upload" class="mw-list-item"><a href="/wiki/Wikipedia:File_Upload_Wizard" title="Upload files [u]" accesskey="u"><span>Upload file</span></a></li><li id="t-specialpages" class="mw-list-item"><a href="/wiki/Special:SpecialPages" title="A list of all special pages [q]" accesskey="q"><span>Special pages</span></a></li><li id="t-permalink" class="mw-list-item"><a href="/w/index.php?title=Mental_calculator&oldid=1238777068" title="Permanent link to this revision of this page"><span>Permanent link</span></a></li><li id="t-info" class="mw-list-item"><a href="/w/index.php?title=Mental_calculator&action=info" title="More information about this page"><span>Page information</span></a></li><li id="t-cite" class="mw-list-item"><a href="/w/index.php?title=Special:CiteThisPage&page=Mental_calculator&id=1238777068&wpFormIdentifier=titleform" title="Information on how to cite this page"><span>Cite this page</span></a></li><li id="t-urlshortener" class="mw-list-item"><a href="/w/index.php?title=Special:UrlShortener&url=https%3A%2F%2Fen.wikipedia.org%2Fw%2Findex.php%3Ftitle%3DMental_calculator%26diff%3D1238777068"><span>Get shortened URL</span></a></li><li id="t-urlshortener-qrcode" class="mw-list-item"><a href="/w/index.php?title=Special:QrCode&url=https%3A%2F%2Fen.wikipedia.org%2Fw%2Findex.php%3Ftitle%3DMental_calculator%26diff%3D1238777068"><span>Download QR code</span></a></li> </ul> </div> </div> <div id="p-coll-print_export" class="vector-menu mw-portlet mw-portlet-coll-print_export" > <div class="vector-menu-heading"> Print/export </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="coll-download-as-rl" class="mw-list-item"><a href="/w/index.php?title=Special:Book&bookcmd=render_article&arttitle=Mental+calculator&returnto=Mental+calculator&oldid=1259467834&writer=rl" title="Download this page as a PDF file"><span>Download as PDF</span></a></li><li id="t-print" class="mw-list-item"><a href="/w/index.php?title=Mental_calculator&printable=yes" title="Printable version of this page [p]" accesskey="p"><span>Printable version</span></a></li> </ul> </div> </div> <div id="p-wikibase-otherprojects" class="vector-menu mw-portlet mw-portlet-wikibase-otherprojects" > <div class="vector-menu-heading"> In other projects </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="wb-otherproject-link wb-otherproject-commons mw-list-item"><a href="https://commons.wikimedia.org/wiki/Category:Mental_calculators" hreflang="en"><span>Wikimedia Commons</span></a></li><li id="t-wikibase" class="wb-otherproject-link wb-otherproject-wikibase-dataitem mw-list-item"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q372646" title="Structured data on this page hosted by Wikidata [g]" accesskey="g"><span>Wikidata item</span></a></li> </ul> </div> </div> </div> </div> </div> </div> </nav> </div> </div> </div> <div class="vector-column-end"> <div class="vector-sticky-pinned-container"> <nav class="vector-page-tools-landmark" aria-label="Page tools"> <div id="vector-page-tools-pinned-container" class="vector-pinned-container"> </div> </nav> <nav class="vector-appearance-landmark" aria-label="Appearance"> <div id="vector-appearance-pinned-container" class="vector-pinned-container"> <div id="vector-appearance" class="vector-appearance vector-pinnable-element"> <div class="vector-pinnable-header vector-appearance-pinnable-header vector-pinnable-header-pinned" data-feature-name="appearance-pinned" data-pinnable-element-id="vector-appearance" data-pinned-container-id="vector-appearance-pinned-container" data-unpinned-container-id="vector-appearance-unpinned-container" > <div class="vector-pinnable-header-label">Appearance</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-appearance.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-appearance.unpin">hide</button> </div> </div> </div> </nav> </div> </div> <div id="bodyContent" class="vector-body" aria-labelledby="firstHeading" data-mw-ve-target-container> <div class="vector-body-before-content"> <div class="mw-indicators"> <div id="mw-indicator-mw-helplink" class="mw-indicator"><a href="https://www.mediawiki.org/wiki/Special:MyLanguage/Help:Diff" target="_blank" class="mw-helplink"><span class="mw-helplink-icon"></span>Help</a></div> </div> <div id="siteSub" class="noprint">From Wikipedia, the free encyclopedia</div> </div> <div id="contentSub"><div id="mw-content-subtitle"></div></div> <div id="mw-content-text" class="mw-body-content"><div class="mw-revslider-container"><span style='width: 100%; text-align: center;' id='ooui-php-1' class='mw-revslider-toggle-button oo-ui-widget oo-ui-widget-enabled oo-ui-buttonElement oo-ui-buttonElement-frameless oo-ui-indicatorElement oo-ui-labelElement oo-ui-buttonWidget' data-ooui='{"_":"OO.ui.ButtonWidget","rel":["nofollow"],"framed":false,"indicator":"down","label":"Browse history interactively","title":"Open revision slider","classes":["mw-revslider-toggle-button"]}'><a role='button' title='Open revision slider' tabindex='0' rel='nofollow' class='oo-ui-buttonElement-button'><span class='oo-ui-iconElement-icon oo-ui-iconElement-noIcon'></span><span class='oo-ui-labelElement-label'>Browse history interactively</span><span class='oo-ui-indicatorElement-indicator oo-ui-indicator-down'></span></a></span><div class="mw-revslider-slider-wrapper" style="display: none;"><div class="mw-revslider-placeholder"><div class="mw-revslider-spinner"><div class="mw-revslider-bounce"></div></div></div></div></div><div class="mw-diff-revision-history-links"><a href="/w/index.php?title=Mental_calculator&diff=prev&oldid=1237480976" class="mw-diff-revision-history-link-previous" title="Mental calculator">← Previous edit</a><a href="/w/index.php?title=Mental_calculator&diff=next&oldid=1238777068" class="mw-diff-revision-history-link-next" title="Mental calculator">Next edit →</a></div><div class="mw-diff-table-prefix" dir="ltr" lang="en"><div class="mw-diff-inline-legend oo-ui-element-hidden"><span class="mw-diff-inline-legend-del">Content deleted</span> <span class="mw-diff-inline-legend-ins">Content added</span></div><div class="ve-init-mw-diffPage-diffMode"><span class='oo-ui-widget oo-ui-widget-enabled oo-ui-buttonGroupWidget'><span aria-disabled='true' class='oo-ui-widget oo-ui-widget-disabled oo-ui-buttonElement oo-ui-buttonElement-framed oo-ui-iconElement oo-ui-labelElement oo-ui-buttonWidget'><a role='button' tabindex='-1' aria-disabled='true' rel='nofollow' class='oo-ui-buttonElement-button'><span class='oo-ui-iconElement-icon oo-ui-icon-eye oo-ui-image-invert'></span><span class='oo-ui-labelElement-label'>Visual</span><span class='oo-ui-indicatorElement-indicator oo-ui-indicatorElement-noIndicator oo-ui-image-invert'></span></a></span><span class='oo-ui-widget oo-ui-widget-enabled oo-ui-buttonElement oo-ui-buttonElement-framed oo-ui-iconElement oo-ui-labelElement oo-ui-buttonWidget oo-ui-buttonElement-active'><a role='button' tabindex='0' rel='nofollow' class='oo-ui-buttonElement-button'><span class='oo-ui-iconElement-icon oo-ui-icon-wikiText oo-ui-image-invert'></span><span class='oo-ui-labelElement-label'>Wikitext</span><span class='oo-ui-indicatorElement-indicator oo-ui-indicatorElement-noIndicator oo-ui-image-invert'></span></a></span></span></div><div class="mw-diffPage-inlineToggle-container"><div id='mw-diffPage-inline-toggle-switch-layout' class='oo-ui-layout oo-ui-labelElement oo-ui-fieldLayout oo-ui-fieldLayout-align-left' data-ooui='{"_":"OO.ui.FieldLayout","fieldWidget":{"tag":"mw-diffPage-inline-toggle-switch"},"$overlay":true,"label":"Inline","title":"Switches between inline format and two-column format"}'><div class='oo-ui-fieldLayout-body'><span class='oo-ui-fieldLayout-header'><label title='Switches between inline format and two-column format' id='ooui-php-2' class='oo-ui-labelElement-label'>Inline</label></span><div class='oo-ui-fieldLayout-field'><div id='mw-diffPage-inline-toggle-switch' title='Switches between inline format and two-column format' aria-checked='false' tabindex='0' role='switch' aria-labelledby='ooui-php-2' class='oo-ui-widget oo-ui-widget-enabled oo-ui-toggleWidget oo-ui-toggleWidget-off oo-ui-toggleSwitchWidget' data-ooui='{"_":"OO.ui.ToggleSwitchWidget","href":"\/w\/index.php?title=Mental_calculator&diff=1238777068&diff-type=inline","value":false,"title":"Switches between inline format and two-column format"}'><span class='oo-ui-toggleSwitchWidget-glow'></span><a href='/w/index.php?title=Mental_calculator&diff=1238777068&diff-type=inline'><span class='oo-ui-toggleSwitchWidget-grip'></span></a></div></div></div></div></div></div><table class="diff diff-type-table diff-contentalign-left diff-editfont-monospace" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr class="diff-title" lang="en"> <td colspan="2" class="diff-otitle diff-side-deleted"><div id="mw-diff-otitle1"><strong><a href="/w/index.php?title=Mental_calculator&oldid=1237480976" title="Mental calculator">Revision as of 01:01, 30 July 2024</a> <span class="mw-diff-edit"><a href="/w/index.php?title=Mental_calculator&action=edit&oldid=1237480976" title="Mental calculator">edit</a></span><span class="mw-diff-timestamp" data-timestamp="2024-07-30T01:01:07Z"></span></strong></div><div id="mw-diff-otitle2"><a href="/w/index.php?title=User:Redbunny30&action=edit&redlink=1" class="new mw-userlink" title="User:Redbunny30 (page does not exist)" data-mw-revid="1237480976"><bdi>Redbunny30</bdi></a> <span class="mw-usertoollinks">(<a href="/w/index.php?title=User_talk:Redbunny30&action=edit&redlink=1" class="new mw-usertoollinks-talk" title="User talk:Redbunny30 (page does not exist)">talk</a> | <a href="/wiki/Special:Contributions/Redbunny30" class="mw-usertoollinks-contribs" title="Special:Contributions/Redbunny30">contribs</a>)</span><div class="mw-diff-usermetadata"><div class="mw-diff-userroles"></div><div class="mw-diff-usereditcount"><span>25</span> edits</div></div></div><div id="mw-diff-otitle3"> <span class="comment comment--without-parentheses"><span class="autocomment"><a href="#Champion_mental_calculators">→<bdi dir="ltr">Champion mental calculators</bdi></a></span></span></div><div id="mw-diff-otitle5"></div><div id="mw-diff-otitle4"><a href="/w/index.php?title=Mental_calculator&diff=prev&oldid=1237480976" title="Mental calculator" id="differences-prevlink">← Previous edit</a></div></td> <td colspan="2" class="diff-ntitle diff-side-added"><div id="mw-diff-ntitle1"><strong><a href="/w/index.php?title=Mental_calculator&oldid=1238777068" title="Mental calculator">Revision as of 16:43, 5 August 2024</a> <span class="mw-diff-edit"><a href="/w/index.php?title=Mental_calculator&action=edit&oldid=1238777068" title="Mental calculator">edit</a></span><span class="mw-diff-timestamp" data-timestamp="2024-08-05T16:43:34Z"></span> <span class="mw-diff-undo"><a href="/w/index.php?title=Mental_calculator&action=edit&undoafter=1237480976&undo=1238777068" title=""Undo" reverts this edit and opens the edit form in preview mode. It allows adding a reason in the summary.">undo</a></span></strong></div><div id="mw-diff-ntitle2"><a href="/w/index.php?title=User:Aliza915&action=edit&redlink=1" class="new mw-userlink" title="User:Aliza915 (page does not exist)" data-mw-revid="1238777068"><bdi>Aliza915</bdi></a> <span class="mw-usertoollinks">(<a href="/wiki/User_talk:Aliza915" class="mw-usertoollinks-talk" title="User talk:Aliza915">talk</a> | <a href="/wiki/Special:Contributions/Aliza915" class="mw-usertoollinks-contribs" title="Special:Contributions/Aliza915">contribs</a>)</span><div class="mw-diff-usermetadata"><div class="mw-diff-userroles"></div><div class="mw-diff-usereditcount"><span>13</span> edits</div></div></div><div id="mw-diff-ntitle3"> <span class="comment comment--without-parentheses"><span class="autocomment"><a href="#External_links">→<bdi dir="ltr">External links</bdi></a></span></span></div><div id="mw-diff-ntitle5"><span class="mw-tag-markers"><a href="/wiki/Special:Tags" title="Special:Tags">Tag</a>: <span class="mw-tag-marker mw-tag-marker-mw-reverted">Reverted</span></span></div><div id="mw-diff-ntitle4"><a href="/w/index.php?title=Mental_calculator&diff=next&oldid=1238777068" title="Mental calculator" id="differences-nextlink">Next edit →</a></div></td> </tr><tr> <td colspan="2" class="diff-lineno">Line 83:</td> <td colspan="2" class="diff-lineno">Line 83:</td> </tr> <tr> <td class="diff-marker"></td> <td class="diff-context diff-side-deleted"><div>*[http://www.recordholders.org/en/events/worldcup/index.html Mental Calculation World Cup site]</div></td> <td class="diff-marker"></td> <td class="diff-context diff-side-added"><div>*[http://www.recordholders.org/en/events/worldcup/index.html Mental Calculation World Cup site]</div></td> </tr> <tr> <td class="diff-marker"></td> <td class="diff-context diff-side-deleted"><div>*[http://www.memoriad.com Memoriad site]</div></td> <td class="diff-marker"></td> <td class="diff-context diff-side-added"><div>*[http://www.memoriad.com Memoriad site]</div></td> </tr> <tr> <td class="diff-marker" data-marker="−"></td> <td class="diff-deletedline diff-side-deleted"><div>*[<del class="diffchange diffchange-inline">http</del>://<del class="diffchange diffchange-inline">users</del>.<del class="diffchange diffchange-inline">lk.net</del>/<del class="diffchange diffchange-inline">~stepanov</del>/<del class="diffchange diffchange-inline">mnemo/pekelise.html Prodigy</del> Calculators by Viktor Pekelis]</div></td> <td class="diff-marker" data-marker="+"></td> <td class="diff-addedline diff-side-added"><div>*[<ins class="diffchange diffchange-inline">https</ins>://<ins class="diffchange diffchange-inline">checkmepcobill</ins>.<ins class="diffchange diffchange-inline">pk</ins>/<ins class="diffchange diffchange-inline">mepco-bill-calculator</ins>/ Calculators by Viktor Pekelis]</div></td> </tr> <tr> <td class="diff-marker"></td> <td class="diff-context diff-side-deleted"><div>*[http://users.lk.net/~stepanov/mnemo/mkleine.html Willem Klein]</div></td> <td class="diff-marker"></td> <td class="diff-context diff-side-added"><div>*[http://users.lk.net/~stepanov/mnemo/mkleine.html Willem Klein]</div></td> </tr> <tr> <td colspan="2" class="diff-empty diff-side-deleted"></td> <td class="diff-marker" data-marker="+"></td> <td class="diff-addedline diff-side-added"><div>*[https://www.thehansindia.com/hans/young-hans/i-love-to-be-quicker-than-anyone-else-bhanu-prakash-526944 Power Calculator]</div></td> </tr> <tr> <td class="diff-marker"></td> <td class="diff-context diff-side-deleted"><div>*[http://users.lk.net/~stepanov/mnemo/fastere.html Thought and machine processes]</div></td> <td class="diff-marker"></td> <td class="diff-context diff-side-added"><div>*[http://users.lk.net/~stepanov/mnemo/fastere.html Thought and machine processes]</div></td> </tr> <tr> <td class="diff-marker"></td> <td class="diff-context diff-side-deleted"><div>*[https://www.thehansindia.com/hans/young-hans/i-love-to-be-quicker-than-anyone-else-bhanu-prakash-526944 Methods and Relevance to Brain efficiency of Neelakantha Bhanu]</div></td> <td class="diff-marker"></td> <td class="diff-context diff-side-added"><div>*[https://www.thehansindia.com/hans/young-hans/i-love-to-be-quicker-than-anyone-else-bhanu-prakash-526944 Methods and Relevance to Brain efficiency of Neelakantha Bhanu]</div></td> </tr> </table><hr class='diff-hr' id='mw-oldid' /> <h2 class='diff-currentversion-title'>Revision as of 16:43, 5 August 2024</h2> <div class="mw-content-ltr mw-parser-output" lang="en" dir="ltr"><div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none">Person exceptionally skilled at mathematical mental calculations</div> <style data-mw-deduplicate="TemplateStyles:r1236090951">.mw-parser-output .hatnote{font-style:italic}.mw-parser-output div.hatnote{padding-left:1.6em;margin-bottom:0.5em}.mw-parser-output .hatnote i{font-style:normal}.mw-parser-output .hatnote+link+.hatnote{margin-top:-0.5em}@media print{body.ns-0 .mw-parser-output .hatnote{display:none!important}}</style><div role="note" class="hatnote navigation-not-searchable">"Human calculator" redirects here. For the systematic use of people for routine calculations, see <a href="/wiki/Human_computer" class="mw-redirect" title="Human computer">Human computer</a>.</div> <style data-mw-deduplicate="TemplateStyles:r1251242444">.mw-parser-output .ambox{border:1px solid #a2a9b1;border-left:10px solid #36c;background-color:#fbfbfb;box-sizing:border-box}.mw-parser-output .ambox+link+.ambox,.mw-parser-output .ambox+link+style+.ambox,.mw-parser-output .ambox+link+link+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+style+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+link+.ambox{margin-top:-1px}html body.mediawiki .mw-parser-output .ambox.mbox-small-left{margin:4px 1em 4px 0;overflow:hidden;width:238px;border-collapse:collapse;font-size:88%;line-height:1.25em}.mw-parser-output .ambox-speedy{border-left:10px solid #b32424;background-color:#fee7e6}.mw-parser-output .ambox-delete{border-left:10px solid #b32424}.mw-parser-output .ambox-content{border-left:10px solid #f28500}.mw-parser-output .ambox-style{border-left:10px solid #fc3}.mw-parser-output .ambox-move{border-left:10px solid #9932cc}.mw-parser-output .ambox-protection{border-left:10px solid #a2a9b1}.mw-parser-output .ambox .mbox-text{border:none;padding:0.25em 0.5em;width:100%}.mw-parser-output .ambox .mbox-image{border:none;padding:2px 0 2px 0.5em;text-align:center}.mw-parser-output .ambox .mbox-imageright{border:none;padding:2px 0.5em 2px 0;text-align:center}.mw-parser-output .ambox .mbox-empty-cell{border:none;padding:0;width:1px}.mw-parser-output .ambox .mbox-image-div{width:52px}@media(min-width:720px){.mw-parser-output .ambox{margin:0 10%}}@media print{body.ns-0 .mw-parser-output .ambox{display:none!important}}</style><table class="box-More_footnotes_needed plainlinks metadata ambox ambox-style ambox-More_footnotes_needed" role="presentation"><tbody><tr><td class="mbox-image"><div class="mbox-image-div"><span typeof="mw:File"><span><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/a/a4/Text_document_with_red_question_mark.svg/40px-Text_document_with_red_question_mark.svg.png" decoding="async" width="40" height="40" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/a/a4/Text_document_with_red_question_mark.svg/60px-Text_document_with_red_question_mark.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/a/a4/Text_document_with_red_question_mark.svg/80px-Text_document_with_red_question_mark.svg.png 2x" data-file-width="48" data-file-height="48" /></span></span></div></td><td class="mbox-text"><div class="mbox-text-span">This article includes a list of <a href="/wiki/Wikipedia:Citing_sources#General_references" title="Wikipedia:Citing sources">general references</a>, but <b>it lacks sufficient corresponding <a href="/wiki/Wikipedia:Citing_sources#Inline_citations" title="Wikipedia:Citing sources">inline citations</a></b>.<span class="hide-when-compact"> Please help to <a href="/wiki/Wikipedia:WikiProject_Reliability" title="Wikipedia:WikiProject Reliability">improve</a> this article by <a href="/wiki/Wikipedia:When_to_cite" title="Wikipedia:When to cite">introducing</a> more precise citations.</span> <span class="date-container"><i>(<span class="date">August 2011</span>)</i></span><span class="hide-when-compact"><i> (<small><a href="/wiki/Help:Maintenance_template_removal" title="Help:Maintenance template removal">Learn how and when to remove this message</a></small>)</i></span></div></td></tr></tbody></table> <figure class="mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:Leonhard_Euler.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/d/d7/Leonhard_Euler.jpg/200px-Leonhard_Euler.jpg" decoding="async" width="200" height="259" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/d/d7/Leonhard_Euler.jpg/300px-Leonhard_Euler.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/d/d7/Leonhard_Euler.jpg/400px-Leonhard_Euler.jpg 2x" data-file-width="4672" data-file-height="6040" /></a><figcaption><a href="/wiki/Leonhard_Euler" title="Leonhard Euler">Leonhard Euler</a> was a prominent mental calculator.</figcaption></figure> <p>A <b>mental calculator</b> or <b>human calculator</b> is a person with a prodigious ability in some area of <a href="/wiki/Mental_calculation" title="Mental calculation">mental calculation</a> (such as <a href="/wiki/Addition" title="Addition">adding</a>, <a href="/wiki/Subtraction" title="Subtraction">subtracting</a>, <a href="/wiki/Multiplication" title="Multiplication">multiplying</a> or <a href="/wiki/Division_(mathematics)" title="Division (mathematics)">dividing</a> large numbers). </p><p>In 2005, a group of researchers led by Michael W. O'Boyle, an American <a href="/wiki/Psychologist" title="Psychologist">psychologist</a> previously working in <a href="/wiki/Australia" title="Australia">Australia</a> and now at <a href="/wiki/Texas_Tech_University" title="Texas Tech University">Texas Tech University</a>, has used <a href="/wiki/MRI" class="mw-redirect" title="MRI">MRI</a> scanning of <a href="/wiki/Blood_flow" class="mw-redirect" title="Blood flow">blood flow</a> during mental operation in computational prodigies. These math prodigies have shown increases in blood flow to parts of the <a href="/wiki/Brain" title="Brain">brain</a> responsible for mathematical operations during a mental rotation task that are greater than the typical increases.<sup id="cite_ref-1" class="reference"><a href="#cite_note-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> </p><p>Mental calculators were in great demand in research centers such as <a href="/wiki/CERN" title="CERN">CERN</a> before the advent of modern electronic calculators and computers. See, for instance, Steven B. Smith's 1983 book <i>The Great Mental Calculators</i>, or the 2016 book <i><a href="/wiki/Hidden_Figures_(book)" title="Hidden Figures (book)">Hidden Figures</a></i><sup id="cite_ref-2" class="reference"><a href="#cite_note-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> and <a href="/wiki/Hidden_Figures" title="Hidden Figures">the film adapted from it</a>. </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="Champion_mental_calculators">Champion mental calculators</h2></div> <p>The <a href="/wiki/Mental_Calculation_World_Cup" title="Mental Calculation World Cup">Mental Calculation World Cup</a> is an international competition that attempts to find the world's best mental calculator, and also the best at specific types of mental calculation, such as multiplication or calendar reckoning. </p><p>The <a href="/wiki/Mind_Sports_Olympiad" title="Mind Sports Olympiad">Mind Sports Olympiad</a> has staged annual world championships since 1998. </p><p>The <a href="/wiki/Mind_Sports_Organisation" title="Mind Sports Organisation">Mind Sports Organisation</a> recognizes six grandmasters of mental calculation: <a href="/wiki/Robert_Fountain_(mental_calculator)" title="Robert Fountain (mental calculator)">Robert Fountain</a> (1999), <a href="/wiki/George_Lane_(mental_calculator)" title="George Lane (mental calculator)">George Lane</a> (2001), <a href="/wiki/Gert_Mittring" title="Gert Mittring">Gert Mittring</a> (2005), Chris Bryant (2017), <a href="/w/index.php?title=Wenzel_Gr%C3%BC%C3%9F&action=edit&redlink=1" class="new" title="Wenzel Grüß (page does not exist)">Wenzel Grüß</a> (2019), and Kaloyan Geshev (2022), and one international master, <a href="/w/index.php?title=Andy_Robertshaw&action=edit&redlink=1" class="new" title="Andy Robertshaw (page does not exist)">Andy Robertshaw</a> (2008). In 2021, Aaryan Nitin Shukla became the youngest champion ever at an age of just 11 years. </p><p><a href="/wiki/Shakuntala_Devi" title="Shakuntala Devi">Shakuntala Devi</a> from <a href="/wiki/India" title="India">India</a> has been often mentioned on the <a href="/wiki/Guinness_World_Records" title="Guinness World Records">Guinness World Records</a>. <a href="/wiki/Neelakantha_Bhanu_Prakash" title="Neelakantha Bhanu Prakash">Neelakantha Bhanu Prakash</a> from <a href="/wiki/India" title="India">India</a> has been often mentioned on the <a href="/wiki/Limca_Book_of_Records" title="Limca Book of Records">Limca Book of Records</a> for racing past the speed of a calculator in addition.<sup id="cite_ref-3" class="reference"><a href="#cite_note-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> Sri Lankan-<a href="/wiki/Malaysian_people" class="mw-redirect" title="Malaysian people">Malaysian</a> performer Yaashwin Sarawanan was the runner-up in 2019 <i><a href="/wiki/Asia%27s_Got_Talent" title="Asia's Got Talent">Asia's Got Talent</a></i>. </p> <div class="mw-heading mw-heading2"><h2 id="Mental_calculators_in_fiction">Mental calculators in fiction</h2></div> <div class="mw-heading mw-heading3"><h3 id="Dune">Dune</h3></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Mentat" class="mw-redirect" title="Mentat">Mentat</a></div> <p>In <a href="/wiki/Frank_Herbert" title="Frank Herbert">Frank Herbert</a>'s novel <i><a href="/wiki/Dune_(novel)" title="Dune (novel)">Dune</a></i>, specially trained mental calculators known as <a href="/wiki/Mentat" class="mw-redirect" title="Mentat">Mentats</a> have replaced mechanical computers completely. Several important supporting characters in the novel, namely <a href="/wiki/Piter_De_Vries" class="mw-redirect" title="Piter De Vries">Piter De Vries</a> and <a href="/wiki/Thufir_Hawat" class="mw-redirect" title="Thufir Hawat">Thufir Hawat</a>, are Mentats. <a href="/wiki/Paul_Atreides" title="Paul Atreides">Paul Atreides</a> was originally trained as one without his knowledge. However, these Mentats do not specialize in mathematical calculations, but in total recall of many different kinds of data. For example, Thufir Hawat is able to recite various details of a mining operation, including the number of various pieces of equipment, the people to work them, the profits and costs involved, etc. In the novel he is never depicted as doing actual academic mathematical calculations. Mentats were valued for their capacity as humans to store data, because "thinking machines" are outlawed. </p> <div class="mw-heading mw-heading3"><h3 id="Matilda">Matilda</h3></div> <p>In <a href="/wiki/Roald_Dahl" title="Roald Dahl">Roald Dahl</a>'s novel <i><a href="/wiki/Matilda_(novel)" title="Matilda (novel)">Matilda</a></i>, the lead character is portrayed having exceptional computational skills as she computes her father's profit without the need for paper computations. During class (she is a first-year elementary school student), she does large-number multiplication problems in her head almost instantly. </p> <div class="mw-heading mw-heading3"><h3 id="Other">Other</h3></div> <p>In the 1988 movie <i><a href="/wiki/Rain_Man" title="Rain Man">Rain Man</a></i>, Raymond Babbitt, who has <a href="/wiki/Savant_syndrome" title="Savant syndrome">savant syndrome</a>, can mentally calculate large numbers, amongst other abilities. </p><p>Andrew Jackson "Slipstick" Libby is a calculating prodigy in <a href="/wiki/Robert_A._Heinlein" title="Robert A. Heinlein">Robert A. Heinlein</a>'s <a href="/wiki/Sci-Fi" class="mw-redirect" title="Sci-Fi">Sci-Fi</a> story <i><a href="/wiki/Methuselah%27s_Children" title="Methuselah's Children">Methuselah's Children</a></i>. </p><p>In the <a href="/wiki/USA_Network" title="USA Network">USA Network</a> legal drama <i><a href="/wiki/Suits_(U.S._TV_series)" class="mw-redirect" title="Suits (U.S. TV series)">Suits</a></i>, the main character, Mike Ross, is asked to multiply considerably large numbers in his head to impress two girls, and subsequently does so. </p><p>In <a href="/wiki/Haruki_Murakami" title="Haruki Murakami">Haruki Murakami</a>'s novel <i><a href="/wiki/Hard-Boiled_Wonderland_and_the_End_of_the_World" title="Hard-Boiled Wonderland and the End of the World">Hard-Boiled Wonderland and the End of the World</a></i>, a class of mental calculators known as <i>Calcutecs</i> perform <a href="/wiki/Cryptography" title="Cryptography">cryptography</a> in a sealed-off portion of their brains, the results of which they are unable to access from their normal waking consciousness. </p><p>In the Fox television show <i><a href="/wiki/Malcolm_in_the_Middle" title="Malcolm in the Middle">Malcolm in the Middle</a></i>, <a href="/wiki/Malcolm_Wilkerson" class="mw-redirect" title="Malcolm Wilkerson">Malcolm Wilkerson</a> displays astounding feats of automatic mental calculation, which causes him to fear his family will see him as a "freak", and causes his brother to ask, "Is Malcolm a robot?". </p><p>In the 1991 movie <i><a href="/wiki/Little_Man_Tate" title="Little Man Tate">Little Man Tate</a></i>, Fred Tate in the audience blurts out the answer during a mental calculation contest. </p><p>In the 1990s NBC TV sitcom <i><a href="/wiki/NewsRadio" title="NewsRadio">NewsRadio</a></i>, reporter/producer Lisa Miller can mentally calculate products, quotients, and square roots effortlessly and almost instantly, on demand. </p><p>In the 1997 Sci-Fi thriller <i><a href="/wiki/Cube_(1997_film)" title="Cube (1997 film)">Cube</a></i>, one of the prisoners, Kazan, appears to be mentally disabled, but is revealed later in the film to be an autistic savant who is able to calculate prime factors in his head. </p><p>In 1998 <a href="/wiki/Darren_Aronofsky" title="Darren Aronofsky">Darren Aronofsky</a>'s film <i><a href="/wiki/Pi_(film)" title="Pi (film)">Pi</a></i>, Maximillian Cohen is asked a few times by a young child with a calculator to do large multiplications and divisions in his head, which he promptly does, correctly. </p><p>In 1998 film <i><a href="/wiki/Mercury_Rising" title="Mercury Rising">Mercury Rising</a></i>, a 9-year-old <a href="/wiki/Autistic_savant" class="mw-redirect" title="Autistic savant">autistic savant</a> with <a href="/wiki/Child_prodigy" title="Child prodigy">prodigious</a> math abilities cracks a <a href="/wiki/Top_secret" class="mw-redirect" title="Top secret">top secret</a> government code. </p><p>In the 2006 film <i><a href="/wiki/Stranger_than_Fiction_(2006_film)" title="Stranger than Fiction (2006 film)">Stranger than Fiction</a></i>, the main character, Harold Crick, is able to perform rapid arithmetic at the request of his co-workers. </p><p>In the 2007 sitcom <i><a href="/wiki/The_Big_Bang_Theory" title="The Big Bang Theory">The Big Bang Theory</a></i>, the main character, <a href="/wiki/Sheldon_Cooper" title="Sheldon Cooper">Sheldon Cooper</a>, calculates numbers and solutions in his head for his theoretical physics research. </p><p>In the 2008 show <i><a href="/wiki/Breaking_Bad" title="Breaking Bad">Breaking Bad</a></i>, the main character, <a href="/wiki/Walter_White_(Breaking_Bad)" title="Walter White (Breaking Bad)">Walter White</a>, is shown to calculate most of the numbers to his deals, such as profit and production costs, purely within his head. </p><p>In the 2009 Japanese animated film <i><a href="/wiki/Summer_Wars" title="Summer Wars">Summer Wars</a></i>, the main character, mathematical genius Kenji Koiso, is able to mentally break purely mathematical encryption codes generated by the OZ virtual world's security system. He can also <a href="/wiki/Calendar_calculation" class="mw-redirect" title="Calendar calculation">mentally calculate the day of the week a person was born</a>, based on their birthday. </p><p>In another Fox television show, <i><a href="/wiki/Fringe_(TV_series)" title="Fringe (TV series)">Fringe</a></i>, in the third episode of the third season, Olivia and her fellow Fringe Division members encounter an individual with severe cognitive impairment who has been given experimental <a href="/wiki/Nootropics" class="mw-redirect" title="Nootropics">nootropics</a> and as a result has become a mathematical genius. The individual is able to calculate hundreds of equations simultaneously, which he leverages to avoid being returned to his original state of cognitive impairment. </p><p>In the 2012 film <i><a href="/wiki/Safe_(2012_film)" title="Safe (2012 film)">Safe</a></i>, a female child math genius is kidnapped to be used by the Chinese Triad. </p><p>In the 2014 TV series <i><a href="/wiki/Scorpion_(TV_series)" title="Scorpion (TV series)">Scorpion</a></i>, Sylvester Dodd, a gifted mathematician and statistician with an IQ of 175; he is described as a "human calculator". </p><p>In the 2016 film <i><a href="/wiki/The_Accountant_(2016_film)" title="The Accountant (2016 film)">The Accountant</a></i>, Christian Wolff is a high-functioning autistic man who tracks insider financial deceptions for numerous criminal organizations. </p><p>In the 2017 film <i><a href="/wiki/Gifted_(2017_film)" title="Gifted (2017 film)">Gifted</a></i>, an intellectually gifted seven-year-old, Mary Adler, becomes the subject of a custody battle between her uncle and grandmother. </p><p>In 2020, an eponymous film <a href="/wiki/Shakuntala_Devi_(film)" title="Shakuntala Devi (film)"><i>Shakuntala Devi</i></a> on the life of Indian mathematician, writer, astrologer and mental calculator <a href="/wiki/Shakuntala_Devi" title="Shakuntala Devi">Shakuntala Devi</a>. </p> <div class="mw-heading mw-heading2"><h2 id="See_also">See also</h2></div> <ul><li><a href="/wiki/Child_prodigy" title="Child prodigy">Child prodigy</a></li> <li><a href="/wiki/Human_computer" class="mw-redirect" title="Human computer">Human computer</a></li> <li><a href="/wiki/Hypercalculia" title="Hypercalculia">Hypercalculia</a></li> <li><a href="/wiki/Mnemonist" title="Mnemonist">Mnemonist</a></li></ul> <div class="mw-heading mw-heading2"><h2 id="References">References</h2></div> <style data-mw-deduplicate="TemplateStyles:r1239543626">.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}</style><div class="reflist"> <div class="mw-references-wrap"><ol class="references"> <li id="cite_note-1"><span class="mw-cite-backlink"><b><a href="#cite_ref-1">^</a></b></span> <span class="reference-text"><style data-mw-deduplicate="TemplateStyles:r1238218222">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}</style><cite id="CITEREFO'Boyle2005" class="citation journal cs1">O'Boyle, Michael W.; et al. (October 2005). "Mathematically gifted male adolescents activate a unique brain network during mental rotation". <i><a href="/wiki/Cognitive_Brain_Research" class="mw-redirect" title="Cognitive Brain Research">Cognitive Brain Research</a></i>. <b>25</b> (2). <a href="/wiki/Amsterdam" title="Amsterdam">Amsterdam</a>: <a href="/wiki/Elsevier" title="Elsevier">Elsevier</a>: 583–587. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1016%2Fj.cogbrainres.2005.08.004">10.1016/j.cogbrainres.2005.08.004</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/16150579">16150579</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Cognitive+Brain+Research&rft.atitle=Mathematically+gifted+male+adolescents+activate+a+unique+brain+network+during+mental+rotation&rft.volume=25&rft.issue=2&rft.pages=583-587&rft.date=2005-10&rft_id=info%3Adoi%2F10.1016%2Fj.cogbrainres.2005.08.004&rft_id=info%3Apmid%2F16150579&rft.aulast=O%27Boyle&rft.aufirst=Michael+W.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMental+calculator" class="Z3988"></span></span> </li> <li id="cite_note-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-2">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFShetterly2016" class="citation book cs1">Shetterly, Margot Lee (2016). <a rel="nofollow" class="external text" href="https://archive.org/details/hiddenfiguresame0000shet/page/115"><i>Hidden Figures: The American Dream and the Untold Story of the Black Women Who Helped Win the Space Race</i></a>. <a href="/wiki/William_Morrow_and_Company" title="William Morrow and Company">William Morrow and Company</a>. pp. <a rel="nofollow" class="external text" href="https://archive.org/details/hiddenfiguresame0000shet/page/115">115</a>. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0062363596" title="Special:BookSources/978-0062363596"><bdi>978-0062363596</bdi></a>. <q>Some of the women were capable of lightning-fast mental math, rivaling their mechanical calculating machines for speed and accuracy. Others, like Dorothy Hoover and Doris Cohen, had highly refined understandings of theoretical math, differentiating their way through nested equations ten pages deep with nary an error in sign. The best of the women made names for themselves for accuracy, speed, and insight.</q></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Hidden+Figures%3A+The+American+Dream+and+the+Untold+Story+of+the+Black+Women+Who+Helped+Win+the+Space+Race&rft.pages=115&rft.pub=William+Morrow+and+Company&rft.date=2016&rft.isbn=978-0062363596&rft.aulast=Shetterly&rft.aufirst=Margot+Lee&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Fhiddenfiguresame0000shet%2Fpage%2F115&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMental+calculator" class="Z3988"></span></span> </li> <li id="cite_note-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-3">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFAdke2019" class="citation web cs1">Adke, Arti (6 May 2019). <a rel="nofollow" class="external text" href="https://www.thehansindia.com/hans/young-hans/i-love-to-be-quicker-than-anyone-else-bhanu-prakash-526944">"I love to be quicker than anyone else, Hans India, May 2019"</a>. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20201209095613/https://www.thehansindia.com/hans/young-hans/i-love-to-be-quicker-than-anyone-else-bhanu-prakash-526944">Archived</a> from the original on 2020-12-09<span class="reference-accessdate">. Retrieved <span class="nowrap">2020-08-17</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=I+love+to+be+quicker+than+anyone+else%2C+Hans+India%2C+May+2019&rft.date=2019-05-06&rft.aulast=Adke&rft.aufirst=Arti&rft_id=https%3A%2F%2Fwww.thehansindia.com%2Fhans%2Fyoung-hans%2Fi-love-to-be-quicker-than-anyone-else-bhanu-prakash-526944&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMental+calculator" class="Z3988"></span></span> </li> </ol></div></div> <div class="mw-heading mw-heading2"><h2 id="Further_reading">Further reading</h2></div> <ul><li>Frank D. Mitchell, "Mathematical Prodigies", The American Journal of Psychology, Vol. 18, No. 1 (Jan., 1907), pp. 61–143 <a href="/wiki/JSTOR_(identifier)" class="mw-redirect" title="JSTOR (identifier)">JSTOR</a> <a rel="nofollow" class="external text" href="https://www.jstor.org/stable/1412172">1412172</a> (free access)</li></ul> <div class="mw-heading mw-heading2"><h2 id="External_links">External links</h2></div> <ul><li><a rel="nofollow" class="external text" href="http://www.recordholders.org/en/events/worldcup/index.html">Mental Calculation World Cup site</a></li> <li><a rel="nofollow" class="external text" href="http://www.memoriad.com">Memoriad site</a></li> <li><a rel="nofollow" class="external text" href="https://checkmepcobill.pk/mepco-bill-calculator/">Calculators by Viktor Pekelis</a></li> <li><a rel="nofollow" class="external text" href="http://users.lk.net/~stepanov/mnemo/mkleine.html">Willem Klein</a></li> <li><a rel="nofollow" class="external text" href="https://www.thehansindia.com/hans/young-hans/i-love-to-be-quicker-than-anyone-else-bhanu-prakash-526944">Power Calculator</a></li> <li><a rel="nofollow" class="external text" href="http://users.lk.net/~stepanov/mnemo/fastere.html">Thought and machine processes</a></li> <li><a rel="nofollow" class="external text" href="https://www.thehansindia.com/hans/young-hans/i-love-to-be-quicker-than-anyone-else-bhanu-prakash-526944">Methods and Relevance to Brain efficiency of Neelakantha Bhanu</a></li> <li><a rel="nofollow" class="external text" href="http://users.lk.net/~stepanov/mnemo/mnemoare.html">Tricks and techniques</a></li> <li><a rel="nofollow" class="external text" href="https://worldmentalcalculation.com/2020/08/16/mso-2020-mental-calculations-online-results/">MSO Results</a></li> <li><a rel="nofollow" class="external text" href="http://myreckonings.com/wordpress/2008/04/15/lightning-calculators-i-the-players/">Lightning Calculators</a> is a three-part essay that discusses these individuals, their methods, and the media coverage of them.</li></ul></div><noscript><img src="https://login.wikimedia.org/wiki/Special:CentralAutoLogin/start?type=1x1" alt="" width="1" height="1" style="border: none; position: absolute;"></noscript> <div class="printfooter" data-nosnippet="">Retrieved from "<a dir="ltr" href="https://en.wikipedia.org/w/index.php?title=Mental_calculator&oldid=1238777068">https://en.wikipedia.org/w/index.php?title=Mental_calculator&oldid=1238777068</a>"</div></div> <div id="catlinks" class="catlinks" data-mw="interface"><div id="mw-normal-catlinks" class="mw-normal-catlinks"><a href="/wiki/Help:Category" title="Help:Category">Categories</a>: <ul><li><a href="/wiki/Category:Mental_calculators" title="Category:Mental calculators">Mental calculators</a></li><li><a href="/wiki/Category:Giftedness" title="Category:Giftedness">Giftedness</a></li></ul></div><div id="mw-hidden-catlinks" class="mw-hidden-catlinks mw-hidden-cats-hidden">Hidden categories: <ul><li><a href="/wiki/Category:Articles_with_short_description" title="Category:Articles with short description">Articles with short description</a></li><li><a href="/wiki/Category:Short_description_is_different_from_Wikidata" title="Category:Short description is different from Wikidata">Short description is different from Wikidata</a></li><li><a href="/wiki/Category:Articles_lacking_in-text_citations_from_August_2011" title="Category:Articles lacking in-text citations from August 2011">Articles lacking in-text citations from August 2011</a></li><li><a href="/wiki/Category:All_articles_lacking_in-text_citations" title="Category:All articles lacking in-text citations">All articles lacking in-text citations</a></li></ul></div></div> </div> </main> </div> <div class="mw-footer-container"> <footer id="footer" class="mw-footer" > <ul id="footer-info"> <li id="footer-info-lastmod"> This page was last edited on 5 August 2024, at 16:43<span class="anonymous-show"> (UTC)</span>.</li> <li id="footer-info-copyright"><span class="nowraplinks">This version of the page has been <a href="/wiki/Help:Page_history" title="Help:Page history">revised</a>. Besides normal editing, the reason for revision may have been that this version contains factual inaccuracies, vandalism, or material not compatible with the <a href="/wiki/Wikipedia:Text_of_the_Creative_Commons_Attribution-ShareAlike_4.0_International_License" title="Wikipedia:Text of the Creative Commons Attribution-ShareAlike 4.0 International License">Creative Commons Attribution-ShareAlike 4.0 License</a>.</span></li> </ul> <ul id="footer-places"> <li id="footer-places-privacy"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Privacy_policy">Privacy policy</a></li> <li id="footer-places-about"><a href="/wiki/Wikipedia:About">About Wikipedia</a></li> <li id="footer-places-disclaimers"><a href="/wiki/Wikipedia:General_disclaimer">Disclaimers</a></li> <li id="footer-places-contact"><a href="//en.wikipedia.org/wiki/Wikipedia:Contact_us">Contact Wikipedia</a></li> <li id="footer-places-wm-codeofconduct"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Universal_Code_of_Conduct">Code of Conduct</a></li> <li id="footer-places-developers"><a href="https://developer.wikimedia.org">Developers</a></li> <li id="footer-places-statslink"><a href="https://stats.wikimedia.org/#/en.wikipedia.org">Statistics</a></li> <li id="footer-places-cookiestatement"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Cookie_statement">Cookie statement</a></li> <li id="footer-places-mobileview"><a href="//en.m.wikipedia.org/w/index.php?title=Mental_calculator&diff=1238777068&mobileaction=toggle_view_mobile" class="noprint stopMobileRedirectToggle">Mobile view</a></li> </ul> <ul id="footer-icons" class="noprint"> <li id="footer-copyrightico"><a href="https://wikimediafoundation.org/" class="cdx-button cdx-button--fake-button cdx-button--size-large cdx-button--fake-button--enabled"><img src="/static/images/footer/wikimedia-button.svg" width="84" height="29" alt="Wikimedia Foundation" loading="lazy"></a></li> <li id="footer-poweredbyico"><a href="https://www.mediawiki.org/" class="cdx-button cdx-button--fake-button cdx-button--size-large cdx-button--fake-button--enabled"><img src="/w/resources/assets/poweredby_mediawiki.svg" alt="Powered by MediaWiki" width="88" height="31" loading="lazy"></a></li> </ul> </footer> </div> </div> </div> <div class="vector-settings" id="p-dock-bottom"> <ul></ul> </div><script>(RLQ=window.RLQ||[]).push(function(){mw.config.set({"wgHostname":"mw-web.codfw.main-7dfb9d98f5-528k5","wgBackendResponseTime":616,"wgPageParseReport":{"limitreport":{"cputime":"0.261","walltime":"0.396","ppvisitednodes":{"value":642,"limit":1000000},"postexpandincludesize":{"value":13989,"limit":2097152},"templateargumentsize":{"value":873,"limit":2097152},"expansiondepth":{"value":13,"limit":100},"expensivefunctioncount":{"value":5,"limit":500},"unstrip-depth":{"value":1,"limit":20},"unstrip-size":{"value":14878,"limit":5000000},"entityaccesscount":{"value":0,"limit":400},"timingprofile":["100.00% 350.167 1 -total"," 45.79% 160.341 1 Template:Reflist"," 35.54% 124.463 1 Template:Cite_journal"," 21.26% 74.452 1 Template:Short_description"," 18.29% 64.039 1 Template:More_footnotes_needed"," 15.97% 55.934 1 Template:Ambox"," 10.90% 38.179 2 Template:Pagetype"," 10.32% 36.147 1 Template:Redirect"," 6.87% 24.053 4 Template:Main_other"," 6.20% 21.724 1 Template:SDcat"]},"scribunto":{"limitreport-timeusage":{"value":"0.160","limit":"10.000"},"limitreport-memusage":{"value":4508462,"limit":52428800}},"cachereport":{"origin":"mw-web.codfw.main-7dfb9d98f5-528k5","timestamp":"20241125204710","ttl":2592000,"transientcontent":false}}});});</script> <script type="application/ld+json">{"@context":"https:\/\/schema.org","@type":"Article","name":"Mental calculator","url":"https:\/\/en.wikipedia.org\/wiki\/Mental_calculator","sameAs":"http:\/\/www.wikidata.org\/entity\/Q372646","mainEntity":"http:\/\/www.wikidata.org\/entity\/Q372646","author":{"@type":"Organization","name":"Contributors to Wikimedia projects"},"publisher":{"@type":"Organization","name":"Wikimedia Foundation, Inc.","logo":{"@type":"ImageObject","url":"https:\/\/www.wikimedia.org\/static\/images\/wmf-hor-googpub.png"}},"datePublished":"2004-02-05T02:32:11Z","dateModified":"2024-08-05T16:43:34Z","image":"https:\/\/upload.wikimedia.org\/wikipedia\/commons\/d\/d7\/Leonhard_Euler.jpg","headline":"person with a prodigious ability in some area of mental calculation"}</script> </body> </html>