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-enabled vector-feature-custom-font-size-clientpref-1 vector-feature-appearance-pinned-clientpref-1 vector-feature-night-mode-disabled skin-theme-clientpref-day vector-toc-available" lang="th" dir="ltr"> <head> <meta charset="UTF-8"> <title>21 - วิกิพีเดีย</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-enabled vector-feature-custom-font-size-clientpref-1 vector-feature-appearance-pinned-clientpref-1 vector-feature-night-mode-disabled skin-theme-clientpref-day vector-toc-available";var cookie=document.cookie.match(/(?:^|; )thwikimwclientpreferences=([^;]+)/);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": "thai","wgMonthNames":["","มกราคม","กุมภาพันธ์","มีนาคม","เมษายน","พฤษภาคม","มิถุนายน","กรกฎาคม","สิงหาคม","กันยายน","ตุลาคม","พฤศจิกายน","ธันวาคม"],"wgRequestId":"2a7b114a-bab5-4d26-aa72-576d8959fce7","wgCanonicalNamespace":"","wgCanonicalSpecialPageName":false,"wgNamespaceNumber":0,"wgPageName":"21","wgTitle":"21","wgCurRevisionId":7391731,"wgRevisionId":7391731,"wgArticleId":36746,"wgIsArticle":true,"wgIsRedirect":false,"wgAction":"view","wgUserName":null,"wgUserGroups":["*"],"wgCategories":["บทความที่มีข้อความภาษาจีน","จำนวนเต็ม"],"wgPageViewLanguage":"th","wgPageContentLanguage":"th","wgPageContentModel":"wikitext","wgRelevantPageName":"21","wgRelevantArticleId":36746,"wgIsProbablyEditable":true,"wgRelevantPageIsProbablyEditable":true, "wgRestrictionEdit":[],"wgRestrictionMove":[],"wgNoticeProject":"wikipedia","wgCiteReferencePreviewsActive":false,"wgMediaViewerOnClick":true,"wgMediaViewerEnabledByDefault":true,"wgPopupsFlags":0,"wgVisualEditor":{"pageLanguageCode":"th","pageLanguageDir":"ltr","pageVariantFallbacks":"th"},"wgMFDisplayWikibaseDescriptions":{"search":true,"watchlist":true,"tagline":true,"nearby":true},"wgWMESchemaEditAttemptStepOversample":false,"wgWMEPageLength":900,"wgRelatedArticlesCompat":[],"wgEditSubmitButtonLabelPublish":true,"wgULSPosition":"interlanguage","wgULSisCompactLinksEnabled":false,"wgVector2022LanguageInHeader":true,"wgULSisLanguageSelectorEmpty":false,"wgWikibaseItemId":"Q712477","wgCheckUserClientHintsHeadersJsApi":["brands","architecture","bitness","fullVersionList","mobile","model","platform","platformVersion"],"GEHomepageSuggestedEditsEnableTopics":true,"wgGETopicsMatchModeEnabled":false,"wgGEStructuredTaskRejectionReasonTextInputEnabled":false,"wgGELevelingUpEnabledForUser": false};RLSTATE={"ext.gadget.charinsert-styles":"ready","ext.globalCssJs.user.styles":"ready","site.styles":"ready","user.styles":"ready","ext.globalCssJs.user":"ready","user":"ready","user.options":"loading","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=["site","mediawiki.page.ready","skins.vector.js","ext.centralNotice.geoIP","ext.centralNotice.startUp","ext.gadget.ReferenceTooltips","ext.gadget.charinsert","ext.gadget.refToolbar","ext.gadget.switcher","ext.urlShortener.toolbar","ext.centralauth.centralautologin","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.growthExperiments.SuggestedEditSession"];</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=th&modules=ext.uls.interlanguage%7Cext.visualEditor.desktopArticleTarget.noscript%7Cext.wikimediaBadges%7Cext.wikimediamessages.styles%7Cskins.vector.icons%2Cstyles%7Cskins.vector.search.codex.styles%7Cwikibase.client.init&only=styles&skin=vector-2022"> <script async="" src="/w/load.php?lang=th&modules=startup&only=scripts&raw=1&skin=vector-2022"></script> <meta name="ResourceLoaderDynamicStyles" content=""> <link rel="stylesheet" href="/w/load.php?lang=th&modules=ext.gadget.charinsert-styles&only=styles&skin=vector-2022"> <link rel="stylesheet" href="/w/load.php?lang=th&modules=site.styles&only=styles&skin=vector-2022"> <meta name="generator" content="MediaWiki 1.44.0-wmf.6"> <meta name="referrer" content="origin"> <meta name="referrer" content="origin-when-cross-origin"> <meta name="robots" content="max-image-preview:standard"> <meta name="format-detection" content="telephone=no"> <meta name="viewport" content="width=1120"> <meta property="og:title" content="21 - วิกิพีเดีย"> <meta property="og:type" content="website"> <link rel="alternate" media="only screen and (max-width: 640px)" href="//th.m.wikipedia.org/wiki/21"> <link rel="alternate" type="application/x-wiki" title="แก้ไข" href="/w/index.php?title=21&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="วิกิพีเดีย (th)"> <link rel="EditURI" type="application/rsd+xml" href="//th.wikipedia.org/w/api.php?action=rsd"> <link rel="canonical" href="https://th.wikipedia.org/wiki/21"> <link rel="license" href="https://creativecommons.org/licenses/by-sa/4.0/deed.th"> <link rel="alternate" type="application/atom+xml" title="ฟีดอะตอม วิกิพีเดีย" href="/w/index.php?title=%E0%B8%9E%E0%B8%B4%E0%B9%80%E0%B8%A8%E0%B8%A9:%E0%B8%9B%E0%B8%A3%E0%B8%B1%E0%B8%9A%E0%B8%9B%E0%B8%A3%E0%B8%B8%E0%B8%87%E0%B8%A5%E0%B9%88%E0%B8%B2%E0%B8%AA%E0%B8%B8%E0%B8%94&feed=atom"> <link rel="dns-prefetch" href="//meta.wikimedia.org" /> <link rel="dns-prefetch" href="login.wikimedia.org"> </head> <body class="skin--responsive skin-vector skin-vector-search-vue mediawiki ltr sitedir-ltr mw-hide-empty-elt ns-0 ns-subject mw-editable page-21 rootpage-21 skin-vector-2022 action-view"><a class="mw-jump-link" href="#bodyContent">ข้ามไปเนื้อหา</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="ไซต์"> <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="เมนูหลัก" > <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">เมนูหลัก</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">เมนูหลัก</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-main-menu.pin">ย้ายเมนูไปที่แถบด้านข้าง</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-main-menu.unpin">ซ่อน</button> </div> <div id="p-navigation" class="vector-menu mw-portlet mw-portlet-navigation" > <div class="vector-menu-heading"> การนำทาง </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="n-mainpage" class="mw-list-item"><a href="/wiki/%E0%B8%AB%E0%B8%99%E0%B9%89%E0%B8%B2%E0%B8%AB%E0%B8%A5%E0%B8%B1%E0%B8%81" title="เยี่ยมชมหน้าหลัก [z]" accesskey="z"><span>หน้าหลัก</span></a></li><li id="n-ask" class="mw-list-item"><a href="/wiki/%E0%B8%A7%E0%B8%B4%E0%B8%81%E0%B8%B4%E0%B8%9E%E0%B8%B5%E0%B9%80%E0%B8%94%E0%B8%B5%E0%B8%A2:%E0%B8%96%E0%B8%B2%E0%B8%A1%E0%B8%84%E0%B8%B3%E0%B8%96%E0%B8%B2%E0%B8%A1"><span>ถามคำถาม</span></a></li><li id="n-currentevents" class="mw-list-item"><a href="/wiki/%E0%B8%AA%E0%B8%96%E0%B8%B2%E0%B8%99%E0%B8%B5%E0%B8%A2%E0%B9%88%E0%B8%AD%E0%B8%A2:%E0%B9%80%E0%B8%AB%E0%B8%95%E0%B8%B8%E0%B8%81%E0%B8%B2%E0%B8%A3%E0%B8%93%E0%B9%8C%E0%B8%9B%E0%B8%B1%E0%B8%88%E0%B8%88%E0%B8%B8%E0%B8%9A%E0%B8%B1%E0%B8%99" title="ค้นหาข้อมูลเบื้องหลังในเหตุการณ์ปัจจุบัน"><span>เหตุการณ์ปัจจุบัน</span></a></li><li id="n-randompage" class="mw-list-item"><a href="/wiki/%E0%B8%9E%E0%B8%B4%E0%B9%80%E0%B8%A8%E0%B8%A9:%E0%B8%AA%E0%B8%B8%E0%B9%88%E0%B8%A1" title="โหลดหน้าแบบสุ่ม [x]" accesskey="x"><span>สุ่มบทความ</span></a></li><li id="n-about" class="mw-list-item"><a href="/wiki/%E0%B8%A7%E0%B8%B4%E0%B8%81%E0%B8%B4%E0%B8%9E%E0%B8%B5%E0%B9%80%E0%B8%94%E0%B8%B5%E0%B8%A2:%E0%B9%80%E0%B8%81%E0%B8%B5%E0%B9%88%E0%B8%A2%E0%B8%A7%E0%B8%81%E0%B8%B1%E0%B8%9A" title="ทำความรู้จักวิกิพีเดีย"><span>เกี่ยวกับวิกิพีเดีย</span></a></li><li id="n-contact" class="mw-list-item"><a href="/wiki/%E0%B8%A7%E0%B8%B4%E0%B8%81%E0%B8%B4%E0%B8%9E%E0%B8%B5%E0%B9%80%E0%B8%94%E0%B8%B5%E0%B8%A2:%E0%B8%95%E0%B8%B4%E0%B8%94%E0%B8%95%E0%B9%88%E0%B8%AD" title="วิธีการติดต่อวิกิพีเดีย"><span>ติดต่อเรา</span></a></li> </ul> </div> </div> <div id="p-interaction" class="vector-menu mw-portlet mw-portlet-interaction" > <div class="vector-menu-heading"> มีส่วนร่วม </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="n-help" class="mw-list-item"><a href="/wiki/%E0%B8%A7%E0%B8%B4%E0%B8%98%E0%B8%B5%E0%B9%83%E0%B8%8A%E0%B9%89:%E0%B8%AA%E0%B8%B2%E0%B8%A3%E0%B8%9A%E0%B8%B1%E0%B8%8D" title="ข้อแนะนำการใช้และแก้ไขวิกิพีเดีย"><span>คำอธิบาย</span></a></li><li id="n-introduction" class="mw-list-item"><a href="/wiki/%E0%B8%A7%E0%B8%B4%E0%B8%81%E0%B8%B4%E0%B8%9E%E0%B8%B5%E0%B9%80%E0%B8%94%E0%B8%B5%E0%B8%A2:%E0%B8%AA%E0%B8%AD%E0%B8%99%E0%B8%81%E0%B8%B2%E0%B8%A3%E0%B9%83%E0%B8%8A%E0%B9%89%E0%B8%87%E0%B8%B2%E0%B8%99"><span>เริ่มต้นเขียน</span></a></li><li id="n-portal" class="mw-list-item"><a href="/wiki/%E0%B8%A7%E0%B8%B4%E0%B8%81%E0%B8%B4%E0%B8%9E%E0%B8%B5%E0%B9%80%E0%B8%94%E0%B8%B5%E0%B8%A2:%E0%B8%A8%E0%B8%B2%E0%B8%A5%E0%B8%B2%E0%B8%9B%E0%B8%A3%E0%B8%B0%E0%B8%8A%E0%B8%B2%E0%B8%84%E0%B8%A1" title="เกี่ยวกับโครงการ สิ่งที่คุณทำได้ และวิธีการค้นหา"><span>ศาลาประชาคม</span></a></li><li id="n-recentchanges" class="mw-list-item"><a href="/wiki/%E0%B8%9E%E0%B8%B4%E0%B9%80%E0%B8%A8%E0%B8%A9:%E0%B8%9B%E0%B8%A3%E0%B8%B1%E0%B8%9A%E0%B8%9B%E0%B8%A3%E0%B8%B8%E0%B8%87%E0%B8%A5%E0%B9%88%E0%B8%B2%E0%B8%AA%E0%B8%B8%E0%B8%94" title="รายการเปลี่ยนแปลงล่าสุดในวิกินี้ [r]" accesskey="r"><span>ปรับปรุงล่าสุด</span></a></li><li id="n-discord" class="mw-list-item"><a href="/wiki/%E0%B8%A7%E0%B8%B4%E0%B8%81%E0%B8%B4%E0%B8%9E%E0%B8%B5%E0%B9%80%E0%B8%94%E0%B8%B5%E0%B8%A2:%E0%B8%94%E0%B8%B4%E0%B8%AA%E0%B8%84%E0%B8%AD%E0%B8%A3%E0%B9%8C%E0%B8%94"><span>ดิสคอร์ด</span></a></li> </ul> </div> </div> </div> </div> </div> </div> </nav> <a href="/wiki/%E0%B8%AB%E0%B8%99%E0%B9%89%E0%B8%B2%E0%B8%AB%E0%B8%A5%E0%B8%B1%E0%B8%81" 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="วิกิพีเดีย" src="/static/images/mobile/copyright/wikipedia-wordmark-th.svg" style="width: 6.4375em; height: 1.6875em;"> <img class="mw-logo-tagline" alt="สารานุกรมเสรี" src="/static/images/mobile/copyright/wikipedia-tagline-th.svg" width="100" height="18" style="width: 6.25em; height: 1.125em;"> </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/%E0%B8%9E%E0%B8%B4%E0%B9%80%E0%B8%A8%E0%B8%A9:%E0%B8%84%E0%B9%89%E0%B8%99%E0%B8%AB%E0%B8%B2" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only search-toggle" title="ค้นหาวิกิ [f]" accesskey="f"><span class="vector-icon mw-ui-icon-search mw-ui-icon-wikimedia-search"></span> <span>ค้นหา</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="ค้นหาใน วิกิพีเดีย" aria-label="ค้นหาใน วิกิพีเดีย" autocapitalize="sentences" title="ค้นหาวิกิ [f]" accesskey="f" id="searchInput" > <span class="cdx-text-input__icon cdx-text-input__start-icon"></span> </div> <input type="hidden" name="title" value="พิเศษ:ค้นหา"> </div> <button class="cdx-button cdx-search-input__end-button">ค้นหา</button> </form> </div> </div> </div> <nav class="vector-user-links vector-user-links-wide" aria-label="เครื่องมือส่วนตัว"> <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="หน้าตา"> <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="หน้าตา" > <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">หน้าตา</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/?wmf_source=donate&wmf_medium=sidebar&wmf_campaign=th.wikipedia.org&uselang=th" class=""><span>บริจาคให้วิกิพีเดีย</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=%E0%B8%9E%E0%B8%B4%E0%B9%80%E0%B8%A8%E0%B8%A9:%E0%B8%AA%E0%B8%A3%E0%B9%89%E0%B8%B2%E0%B8%87%E0%B8%9A%E0%B8%B1%E0%B8%8D%E0%B8%8A%E0%B8%B5%E0%B8%9C%E0%B8%B9%E0%B9%89%E0%B9%83%E0%B8%8A%E0%B9%89%E0%B9%83%E0%B8%AB%E0%B8%A1%E0%B9%88&returnto=21" title="แนะนำให้คุณสร้างบัญชีและเข้าสู่ระบบ แต่ไม่บังคับ" class=""><span>สร้างบัญชี</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=%E0%B8%9E%E0%B8%B4%E0%B9%80%E0%B8%A8%E0%B8%A9:%E0%B8%A5%E0%B9%87%E0%B8%AD%E0%B8%81%E0%B8%AD%E0%B8%B4%E0%B8%99&returnto=21" title="แนะนำให้คุณเข้าสู่ระบบ แต่ไม่บังคับ [o]" accesskey="o" class=""><span>เข้าสู่ระบบ</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="ตัวเลือกเพิ่มเติม" > <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="เครื่องมือส่วนตัว" > <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">เครื่องมือส่วนตัว</span> </label> <div class="vector-dropdown-content"> <div id="p-personal" class="vector-menu mw-portlet mw-portlet-personal user-links-collapsible-item" title="เมนูผู้ใช้" > <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/?wmf_source=donate&wmf_medium=sidebar&wmf_campaign=th.wikipedia.org&uselang=th"><span>บริจาคให้วิกิพีเดีย</span></a></li><li id="pt-createaccount" class="user-links-collapsible-item mw-list-item"><a href="/w/index.php?title=%E0%B8%9E%E0%B8%B4%E0%B9%80%E0%B8%A8%E0%B8%A9:%E0%B8%AA%E0%B8%A3%E0%B9%89%E0%B8%B2%E0%B8%87%E0%B8%9A%E0%B8%B1%E0%B8%8D%E0%B8%8A%E0%B8%B5%E0%B8%9C%E0%B8%B9%E0%B9%89%E0%B9%83%E0%B8%8A%E0%B9%89%E0%B9%83%E0%B8%AB%E0%B8%A1%E0%B9%88&returnto=21" title="แนะนำให้คุณสร้างบัญชีและเข้าสู่ระบบ แต่ไม่บังคับ"><span class="vector-icon mw-ui-icon-userAdd mw-ui-icon-wikimedia-userAdd"></span> <span>สร้างบัญชี</span></a></li><li id="pt-login" class="user-links-collapsible-item mw-list-item"><a href="/w/index.php?title=%E0%B8%9E%E0%B8%B4%E0%B9%80%E0%B8%A8%E0%B8%A9:%E0%B8%A5%E0%B9%87%E0%B8%AD%E0%B8%81%E0%B8%AD%E0%B8%B4%E0%B8%99&returnto=21" title="แนะนำให้คุณเข้าสู่ระบบ แต่ไม่บังคับ [o]" accesskey="o"><span class="vector-icon mw-ui-icon-logIn mw-ui-icon-wikimedia-logIn"></span> <span>เข้าสู่ระบบ</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"> หน้าสำหรับผู้แก้ไขที่ออกจากระบบ <a href="/wiki/%E0%B8%A7%E0%B8%B4%E0%B8%98%E0%B8%B5%E0%B9%83%E0%B8%8A%E0%B9%89:%E0%B8%9A%E0%B8%97%E0%B8%99%E0%B8%B3" aria-label="เรียนรู้เพิ่มเกี่ยวกับการแก้ไข"><span>เรียนรู้เพิ่มเติม</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/%E0%B8%9E%E0%B8%B4%E0%B9%80%E0%B8%A8%E0%B8%A9:%E0%B9%80%E0%B8%A3%E0%B8%B7%E0%B9%88%E0%B8%AD%E0%B8%87%E0%B8%97%E0%B8%B5%E0%B9%88%E0%B8%89%E0%B8%B1%E0%B8%99%E0%B9%80%E0%B8%82%E0%B8%B5%E0%B8%A2%E0%B8%99" title="รายการการแก้ไขจากเลขที่อยู่ไอพีนี้ [y]" accesskey="y"><span>ส่วนร่วม</span></a></li><li id="pt-anontalk" class="mw-list-item"><a href="/wiki/%E0%B8%9E%E0%B8%B4%E0%B9%80%E0%B8%A8%E0%B8%A9:%E0%B8%AB%E0%B8%99%E0%B9%89%E0%B8%B2%E0%B8%9E%E0%B8%B9%E0%B8%94%E0%B8%84%E0%B8%B8%E0%B8%A2%E0%B8%82%E0%B8%AD%E0%B8%87%E0%B8%89%E0%B8%B1%E0%B8%99" title="อภิปรายเกี่ยวกับการแก้ไขจากเลขที่อยู่ไอพีนี้ [n]" accesskey="n"><span>คุย</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="ไซต์"> <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="สารบัญ" 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">สารบัญ</h2> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-toc.pin">ย้ายเมนูไปที่แถบด้านข้าง</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-toc.unpin">ซ่อน</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">บทนำ</div> </a> </li> <li id="toc-คำเติมนำหน้า" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#คำเติมนำหน้า"> <div class="vector-toc-text"> <span class="vector-toc-numb">1</span> <span>คำเติมนำหน้า</span> </div> </a> <ul id="toc-คำเติมนำหน้า-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-ความหมาย" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#ความหมาย"> <div class="vector-toc-text"> <span class="vector-toc-numb">2</span> <span>ความหมาย</span> </div> </a> <ul id="toc-ความหมาย-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-ในทางคณิตศาสตร์" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#ในทางคณิตศาสตร์"> <div class="vector-toc-text"> <span class="vector-toc-numb">3</span> <span>ในทางคณิตศาสตร์</span> </div> </a> <ul id="toc-ในทางคณิตศาสตร์-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="สารบัญ" 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"><span class="mw-page-title-main">21</span></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="ไปที่บทความในภาษาอื่น ซึ่งมีใน 97 ภาษา" > <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-97" 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">97 ภาษา</span> </label> <div class="vector-dropdown-content"> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="interlanguage-link interwiki-ab mw-list-item"><a href="https://ab.wikipedia.org/wiki/21_(%D0%B0%D1%85%D1%8B%D4%A5%D1%85%D1%8C%D0%B0%D3%A1%D0%B0%D1%80%D0%B0)" title="21 (ахыԥхьаӡара) – อับฮาเซีย" lang="ab" hreflang="ab" data-title="21 (ахыԥхьаӡара)" data-language-autonym="Аԥсшәа" data-language-local-name="อับฮาเซีย" class="interlanguage-link-target"><span>Аԥсшәа</span></a></li><li class="interlanguage-link interwiki-ar mw-list-item"><a href="https://ar.wikipedia.org/wiki/21_(%D8%B9%D8%AF%D8%AF)" title="21 (عدد) – อาหรับ" lang="ar" hreflang="ar" data-title="21 (عدد)" data-language-autonym="العربية" data-language-local-name="อาหรับ" class="interlanguage-link-target"><span>العربية</span></a></li><li class="interlanguage-link interwiki-ary mw-list-item"><a href="https://ary.wikipedia.org/wiki/21" title="21 – อาหรับโมร็อกโก" lang="ary" hreflang="ary" data-title="21" data-language-autonym="الدارجة" data-language-local-name="อาหรับโมร็อกโก" class="interlanguage-link-target"><span>الدارجة</span></a></li><li class="interlanguage-link interwiki-az mw-list-item"><a href="https://az.wikipedia.org/wiki/21_(%C9%99d%C9%99d)" title="21 (ədəd) – อาเซอร์ไบจาน" lang="az" hreflang="az" data-title="21 (ədəd)" data-language-autonym="Azərbaycanca" data-language-local-name="อาเซอร์ไบจาน" class="interlanguage-link-target"><span>Azərbaycanca</span></a></li><li class="interlanguage-link interwiki-azb mw-list-item"><a href="https://azb.wikipedia.org/wiki/%DB%B2%DB%B1_(%D8%B3%D8%A7%DB%8C%DB%8C)" title="۲۱ (سایی) – South Azerbaijani" lang="azb" hreflang="azb" data-title="۲۱ (سایی)" data-language-autonym="تۆرکجه" data-language-local-name="South Azerbaijani" class="interlanguage-link-target"><span>تۆرکجه</span></a></li><li class="interlanguage-link interwiki-ban mw-list-item"><a href="https://ban.wikipedia.org/wiki/21_(angka)" title="21 (angka) – บาหลี" lang="ban" hreflang="ban" data-title="21 (angka)" data-language-autonym="Basa Bali" data-language-local-name="บาหลี" class="interlanguage-link-target"><span>Basa Bali</span></a></li><li class="interlanguage-link interwiki-bg mw-list-item"><a href="https://bg.wikipedia.org/wiki/21_(%D1%87%D0%B8%D1%81%D0%BB%D0%BE)" title="21 (число) – บัลแกเรีย" lang="bg" hreflang="bg" data-title="21 (число)" data-language-autonym="Български" data-language-local-name="บัลแกเรีย" class="interlanguage-link-target"><span>Български</span></a></li><li class="interlanguage-link interwiki-bo mw-list-item"><a href="https://bo.wikipedia.org/wiki/%E0%BC%A2%E0%BC%A1_(%E0%BD%82%E0%BE%B2%E0%BD%84%E0%BD%A6%E0%BC%8B%E0%BD%80%E0%BC%8D)" title="༢༡ (གྲངས་ཀ།) – ทิเบต" lang="bo" hreflang="bo" data-title="༢༡ (གྲངས་ཀ།)" data-language-autonym="བོད་ཡིག" data-language-local-name="ทิเบต" class="interlanguage-link-target"><span>བོད་ཡིག</span></a></li><li class="interlanguage-link interwiki-ca mw-list-item"><a href="https://ca.wikipedia.org/wiki/Vint-i-u" title="Vint-i-u – คาตาลัน" lang="ca" hreflang="ca" data-title="Vint-i-u" data-language-autonym="Català" data-language-local-name="คาตาลัน" class="interlanguage-link-target"><span>Català</span></a></li><li class="interlanguage-link interwiki-cdo mw-list-item"><a href="https://cdo.wikipedia.org/wiki/21" title="21 – Mindong" lang="cdo" hreflang="cdo" data-title="21" data-language-autonym="閩東語 / Mìng-dĕ̤ng-ngṳ̄" data-language-local-name="Mindong" class="interlanguage-link-target"><span>閩東語 / Mìng-dĕ̤ng-ngṳ̄</span></a></li><li class="interlanguage-link interwiki-ckb mw-list-item"><a href="https://ckb.wikipedia.org/wiki/%D9%A2%D9%A1_(%DA%98%D9%85%D8%A7%D8%B1%DB%95)" title="٢١ (ژمارە) – เคิร์ดตอนกลาง" lang="ckb" hreflang="ckb" data-title="٢١ (ژمارە)" data-language-autonym="کوردی" data-language-local-name="เคิร์ดตอนกลาง" class="interlanguage-link-target"><span>کوردی</span></a></li><li class="interlanguage-link interwiki-cs mw-list-item"><a href="https://cs.wikipedia.org/wiki/21_(%C4%8D%C3%ADslo)" title="21 (číslo) – เช็ก" lang="cs" hreflang="cs" data-title="21 (číslo)" data-language-autonym="Čeština" data-language-local-name="เช็ก" class="interlanguage-link-target"><span>Čeština</span></a></li><li class="interlanguage-link interwiki-cv mw-list-item"><a href="https://cv.wikipedia.org/wiki/21_(%D1%85%D0%B8%D1%81%D0%B5%D0%BF)" title="21 (хисеп) – ชูวัช" lang="cv" hreflang="cv" data-title="21 (хисеп)" data-language-autonym="Чӑвашла" data-language-local-name="ชูวัช" class="interlanguage-link-target"><span>Чӑвашла</span></a></li><li class="interlanguage-link interwiki-cy mw-list-item"><a href="https://cy.wikipedia.org/wiki/21_(rhif)" title="21 (rhif) – เวลส์" lang="cy" hreflang="cy" data-title="21 (rhif)" data-language-autonym="Cymraeg" data-language-local-name="เวลส์" class="interlanguage-link-target"><span>Cymraeg</span></a></li><li class="interlanguage-link interwiki-da mw-list-item"><a href="https://da.wikipedia.org/wiki/21_(tal)" title="21 (tal) – เดนมาร์ก" lang="da" hreflang="da" data-title="21 (tal)" data-language-autonym="Dansk" data-language-local-name="เดนมาร์ก" class="interlanguage-link-target"><span>Dansk</span></a></li><li class="interlanguage-link interwiki-de mw-list-item"><a href="https://de.wikipedia.org/wiki/Einundzwanzig" title="Einundzwanzig – เยอรมัน" lang="de" hreflang="de" data-title="Einundzwanzig" data-language-autonym="Deutsch" data-language-local-name="เยอรมัน" class="interlanguage-link-target"><span>Deutsch</span></a></li><li class="interlanguage-link interwiki-el mw-list-item"><a href="https://el.wikipedia.org/wiki/21_(%CE%B1%CF%81%CE%B9%CE%B8%CE%BC%CF%8C%CF%82)" title="21 (αριθμός) – กรีก" lang="el" hreflang="el" data-title="21 (αριθμός)" data-language-autonym="Ελληνικά" data-language-local-name="กรีก" class="interlanguage-link-target"><span>Ελληνικά</span></a></li><li class="interlanguage-link interwiki-eml mw-list-item"><a href="https://eml.wikipedia.org/wiki/21_(n%C3%B9mer)" title="21 (nùmer) – Emiliano-Romagnolo" lang="egl" hreflang="egl" data-title="21 (nùmer)" data-language-autonym="Emiliàn e rumagnòl" data-language-local-name="Emiliano-Romagnolo" class="interlanguage-link-target"><span>Emiliàn e rumagnòl</span></a></li><li class="interlanguage-link interwiki-en mw-list-item"><a href="https://en.wikipedia.org/wiki/21_(number)" title="21 (number) – อังกฤษ" lang="en" hreflang="en" data-title="21 (number)" data-language-autonym="English" data-language-local-name="อังกฤษ" class="interlanguage-link-target"><span>English</span></a></li><li class="interlanguage-link interwiki-eo mw-list-item"><a href="https://eo.wikipedia.org/wiki/21_(nombro)" title="21 (nombro) – เอสเปรันโต" lang="eo" hreflang="eo" data-title="21 (nombro)" data-language-autonym="Esperanto" data-language-local-name="เอสเปรันโต" class="interlanguage-link-target"><span>Esperanto</span></a></li><li class="interlanguage-link interwiki-es mw-list-item"><a href="https://es.wikipedia.org/wiki/Veintiuno" title="Veintiuno – สเปน" lang="es" hreflang="es" data-title="Veintiuno" data-language-autonym="Español" data-language-local-name="สเปน" class="interlanguage-link-target"><span>Español</span></a></li><li class="interlanguage-link interwiki-eu mw-list-item"><a href="https://eu.wikipedia.org/wiki/Hogeita_bat" title="Hogeita bat – บาสก์" lang="eu" hreflang="eu" data-title="Hogeita bat" data-language-autonym="Euskara" data-language-local-name="บาสก์" class="interlanguage-link-target"><span>Euskara</span></a></li><li class="interlanguage-link interwiki-fa mw-list-item"><a href="https://fa.wikipedia.org/wiki/%DB%B2%DB%B1_(%D8%B9%D8%AF%D8%AF)" title="۲۱ (عدد) – เปอร์เซีย" lang="fa" hreflang="fa" data-title="۲۱ (عدد)" data-language-autonym="فارسی" data-language-local-name="เปอร์เซีย" class="interlanguage-link-target"><span>فارسی</span></a></li><li class="interlanguage-link interwiki-ff mw-list-item"><a href="https://ff.wikipedia.org/wiki/Noogas_e_go%E2%80%99o" title="Noogas e go’o – ฟูลาห์" lang="ff" hreflang="ff" data-title="Noogas e go’o" data-language-autonym="Fulfulde" data-language-local-name="ฟูลาห์" class="interlanguage-link-target"><span>Fulfulde</span></a></li><li class="interlanguage-link interwiki-fi mw-list-item"><a href="https://fi.wikipedia.org/wiki/21_(luku)" title="21 (luku) – ฟินแลนด์" lang="fi" hreflang="fi" data-title="21 (luku)" data-language-autonym="Suomi" data-language-local-name="ฟินแลนด์" class="interlanguage-link-target"><span>Suomi</span></a></li><li class="interlanguage-link interwiki-fj mw-list-item"><a href="https://fj.wikipedia.org/wiki/Rua_ka_dua" title="Rua ka dua – ฟิจิ" lang="fj" hreflang="fj" data-title="Rua ka dua" data-language-autonym="Na Vosa Vakaviti" data-language-local-name="ฟิจิ" class="interlanguage-link-target"><span>Na Vosa Vakaviti</span></a></li><li class="interlanguage-link interwiki-fo mw-list-item"><a href="https://fo.wikipedia.org/wiki/21_(tal)" title="21 (tal) – แฟโร" lang="fo" hreflang="fo" data-title="21 (tal)" data-language-autonym="Føroyskt" data-language-local-name="แฟโร" class="interlanguage-link-target"><span>Føroyskt</span></a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikipedia.org/wiki/21_(nombre)" title="21 (nombre) – ฝรั่งเศส" lang="fr" hreflang="fr" data-title="21 (nombre)" data-language-autonym="Français" data-language-local-name="ฝรั่งเศส" class="interlanguage-link-target"><span>Français</span></a></li><li class="interlanguage-link interwiki-ga mw-list-item"><a href="https://ga.wikipedia.org/wiki/21_(uimhir)" title="21 (uimhir) – ไอริช" lang="ga" hreflang="ga" data-title="21 (uimhir)" data-language-autonym="Gaeilge" data-language-local-name="ไอริช" class="interlanguage-link-target"><span>Gaeilge</span></a></li><li class="interlanguage-link interwiki-gan mw-list-item"><a href="https://gan.wikipedia.org/wiki/21" title="21 – จีนกั้น" lang="gan" hreflang="gan" data-title="21" data-language-autonym="贛語" data-language-local-name="จีนกั้น" class="interlanguage-link-target"><span>贛語</span></a></li><li class="interlanguage-link interwiki-ha mw-list-item"><a href="https://ha.wikipedia.org/wiki/21_(al%C6%99alami)" title="21 (alƙalami) – เฮาซา" lang="ha" hreflang="ha" data-title="21 (alƙalami)" data-language-autonym="Hausa" data-language-local-name="เฮาซา" class="interlanguage-link-target"><span>Hausa</span></a></li><li class="interlanguage-link interwiki-he mw-list-item"><a href="https://he.wikipedia.org/wiki/21_(%D7%9E%D7%A1%D7%A4%D7%A8)" title="21 (מספר) – ฮิบรู" lang="he" hreflang="he" data-title="21 (מספר)" data-language-autonym="עברית" data-language-local-name="ฮิบรู" class="interlanguage-link-target"><span>עברית</span></a></li><li class="interlanguage-link interwiki-hi mw-list-item"><a href="https://hi.wikipedia.org/wiki/%E0%A5%A8%E0%A5%A7_(%E0%A4%B8%E0%A4%82%E0%A4%96%E0%A5%8D%E0%A4%AF%E0%A4%BE)" title="२१ (संख्या) – ฮินดี" lang="hi" hreflang="hi" data-title="२१ (संख्या)" data-language-autonym="हिन्दी" data-language-local-name="ฮินดี" class="interlanguage-link-target"><span>हिन्दी</span></a></li><li class="interlanguage-link interwiki-ht mw-list-item"><a href="https://ht.wikipedia.org/wiki/21_(nonm)" title="21 (nonm) – เฮติครีโอล" lang="ht" hreflang="ht" data-title="21 (nonm)" data-language-autonym="Kreyòl ayisyen" data-language-local-name="เฮติครีโอล" class="interlanguage-link-target"><span>Kreyòl ayisyen</span></a></li><li class="interlanguage-link interwiki-hu mw-list-item"><a href="https://hu.wikipedia.org/wiki/21_(sz%C3%A1m)" title="21 (szám) – ฮังการี" lang="hu" hreflang="hu" data-title="21 (szám)" data-language-autonym="Magyar" data-language-local-name="ฮังการี" class="interlanguage-link-target"><span>Magyar</span></a></li><li class="interlanguage-link interwiki-hy mw-list-item"><a href="https://hy.wikipedia.org/wiki/21_(%D5%A9%D5%AB%D5%BE)" title="21 (թիվ) – อาร์เมเนีย" lang="hy" hreflang="hy" data-title="21 (թիվ)" data-language-autonym="Հայերեն" data-language-local-name="อาร์เมเนีย" class="interlanguage-link-target"><span>Հայերեն</span></a></li><li class="interlanguage-link interwiki-ia mw-list-item"><a href="https://ia.wikipedia.org/wiki/21_(numero)" title="21 (numero) – อินเตอร์ลิงกัว" lang="ia" hreflang="ia" data-title="21 (numero)" data-language-autonym="Interlingua" data-language-local-name="อินเตอร์ลิงกัว" class="interlanguage-link-target"><span>Interlingua</span></a></li><li class="interlanguage-link interwiki-id mw-list-item"><a href="https://id.wikipedia.org/wiki/21_(angka)" title="21 (angka) – อินโดนีเซีย" lang="id" hreflang="id" data-title="21 (angka)" data-language-autonym="Bahasa Indonesia" data-language-local-name="อินโดนีเซีย" class="interlanguage-link-target"><span>Bahasa Indonesia</span></a></li><li class="interlanguage-link interwiki-ig mw-list-item"><a href="https://ig.wikipedia.org/wiki/Iri_ab%E1%BB%A5o_na_otu" title="Iri abụo na otu – อิกโบ" lang="ig" hreflang="ig" data-title="Iri abụo na otu" data-language-autonym="Igbo" data-language-local-name="อิกโบ" class="interlanguage-link-target"><span>Igbo</span></a></li><li class="interlanguage-link interwiki-ik mw-list-item"><a href="https://ik.wikipedia.org/wiki/I%C3%B1ui%C3%B1aq_atausiq" title="Iñuiñaq atausiq – อีนูเปียก" lang="ik" hreflang="ik" data-title="Iñuiñaq atausiq" data-language-autonym="Iñupiatun" data-language-local-name="อีนูเปียก" class="interlanguage-link-target"><span>Iñupiatun</span></a></li><li class="interlanguage-link interwiki-it mw-list-item"><a href="https://it.wikipedia.org/wiki/21_(numero)" title="21 (numero) – อิตาลี" lang="it" hreflang="it" data-title="21 (numero)" data-language-autonym="Italiano" data-language-local-name="อิตาลี" class="interlanguage-link-target"><span>Italiano</span></a></li><li class="interlanguage-link interwiki-ja mw-list-item"><a href="https://ja.wikipedia.org/wiki/21" title="21 – ญี่ปุ่น" lang="ja" hreflang="ja" data-title="21" data-language-autonym="日本語" data-language-local-name="ญี่ปุ่น" class="interlanguage-link-target"><span>日本語</span></a></li><li class="interlanguage-link interwiki-ka mw-list-item"><a href="https://ka.wikipedia.org/wiki/21_(%E1%83%A0%E1%83%98%E1%83%AA%E1%83%AE%E1%83%95%E1%83%98)" title="21 (რიცხვი) – จอร์เจีย" lang="ka" hreflang="ka" data-title="21 (რიცხვი)" data-language-autonym="ქართული" data-language-local-name="จอร์เจีย" class="interlanguage-link-target"><span>ქართული</span></a></li><li class="interlanguage-link interwiki-kcg mw-list-item"><a href="https://kcg.wikipedia.org/wiki/21_(la%CC%B1mba)" title="21 (la̱mba) – ทีแยป" lang="kcg" hreflang="kcg" data-title="21 (la̱mba)" data-language-autonym="Tyap" data-language-local-name="ทีแยป" class="interlanguage-link-target"><span>Tyap</span></a></li><li class="interlanguage-link interwiki-ko mw-list-item"><a href="https://ko.wikipedia.org/wiki/21" title="21 – เกาหลี" lang="ko" hreflang="ko" data-title="21" data-language-autonym="한국어" data-language-local-name="เกาหลี" class="interlanguage-link-target"><span>한국어</span></a></li><li class="interlanguage-link interwiki-ks mw-list-item"><a href="https://ks.wikipedia.org/wiki/21_(%DA%AF%D8%B1%D9%8E%D9%9B%D9%86%D9%9B%D8%AF)" title="21 (گرَٛنٛد) – แคชเมียร์" lang="ks" hreflang="ks" data-title="21 (گرَٛنٛد)" data-language-autonym="कॉशुर / کٲشُر" data-language-local-name="แคชเมียร์" class="interlanguage-link-target"><span>कॉशुर / کٲشُر</span></a></li><li class="interlanguage-link interwiki-la mw-list-item"><a href="https://la.wikipedia.org/wiki/Viginti_unus" title="Viginti unus – ละติน" lang="la" hreflang="la" data-title="Viginti unus" data-language-autonym="Latina" data-language-local-name="ละติน" class="interlanguage-link-target"><span>Latina</span></a></li><li class="interlanguage-link interwiki-lbe mw-list-item"><a href="https://lbe.wikipedia.org/wiki/%D0%9A%D1%8C%D1%83%D0%BD%D0%B8%D1%8F_%D1%86%D0%B0%D0%B2%D0%B0" title="Кьуния цава – Lak" lang="lbe" hreflang="lbe" data-title="Кьуния цава" data-language-autonym="Лакку" data-language-local-name="Lak" class="interlanguage-link-target"><span>Лакку</span></a></li><li class="interlanguage-link interwiki-lg mw-list-item"><a href="https://lg.wikipedia.org/wiki/Abiri_mu_emu" title="Abiri mu emu – ยูกันดา" lang="lg" hreflang="lg" data-title="Abiri mu emu" data-language-autonym="Luganda" data-language-local-name="ยูกันดา" class="interlanguage-link-target"><span>Luganda</span></a></li><li class="interlanguage-link interwiki-ln mw-list-item"><a href="https://ln.wikipedia.org/wiki/21_(motuya)" title="21 (motuya) – ลิงกาลา" lang="ln" hreflang="ln" data-title="21 (motuya)" data-language-autonym="Lingála" data-language-local-name="ลิงกาลา" class="interlanguage-link-target"><span>Lingála</span></a></li><li class="interlanguage-link interwiki-lt mw-list-item"><a href="https://lt.wikipedia.org/wiki/21_(skai%C4%8Dius)" title="21 (skaičius) – ลิทัวเนีย" lang="lt" hreflang="lt" data-title="21 (skaičius)" data-language-autonym="Lietuvių" data-language-local-name="ลิทัวเนีย" class="interlanguage-link-target"><span>Lietuvių</span></a></li><li class="interlanguage-link interwiki-lv mw-list-item"><a href="https://lv.wikipedia.org/wiki/21_(skaitlis)" title="21 (skaitlis) – ลัตเวีย" lang="lv" hreflang="lv" data-title="21 (skaitlis)" data-language-autonym="Latviešu" data-language-local-name="ลัตเวีย" class="interlanguage-link-target"><span>Latviešu</span></a></li><li class="interlanguage-link interwiki-mai mw-list-item"><a href="https://mai.wikipedia.org/wiki/%E0%A5%A8%E0%A5%A7" title="२१ – ไมถิลี" lang="mai" hreflang="mai" data-title="२१" data-language-autonym="मैथिली" data-language-local-name="ไมถิลี" class="interlanguage-link-target"><span>मैथिली</span></a></li><li class="interlanguage-link interwiki-mk mw-list-item"><a href="https://mk.wikipedia.org/wiki/21_(%D0%B1%D1%80%D0%BE%D1%98)" title="21 (број) – มาซิโดเนีย" lang="mk" hreflang="mk" data-title="21 (број)" data-language-autonym="Македонски" data-language-local-name="มาซิโดเนีย" class="interlanguage-link-target"><span>Македонски</span></a></li><li class="interlanguage-link interwiki-mni mw-list-item"><a href="https://mni.wikipedia.org/wiki/%EA%AF%B2%EA%AF%B1" title="꯲꯱ – มณีปุระ" lang="mni" hreflang="mni" data-title="꯲꯱" data-language-autonym="ꯃꯤꯇꯩ ꯂꯣꯟ" data-language-local-name="มณีปุระ" class="interlanguage-link-target"><span>ꯃꯤꯇꯩ ꯂꯣꯟ</span></a></li><li class="interlanguage-link interwiki-mr mw-list-item"><a href="https://mr.wikipedia.org/wiki/%E0%A5%A8%E0%A5%A7_(%E0%A4%B8%E0%A4%82%E0%A4%96%E0%A5%8D%E0%A4%AF%E0%A4%BE)" title="२१ (संख्या) – มราฐี" lang="mr" hreflang="mr" data-title="२१ (संख्या)" data-language-autonym="मराठी" data-language-local-name="มราฐี" class="interlanguage-link-target"><span>मराठी</span></a></li><li class="interlanguage-link interwiki-ms mw-list-item"><a href="https://ms.wikipedia.org/wiki/21_(nombor)" title="21 (nombor) – มาเลย์" lang="ms" hreflang="ms" data-title="21 (nombor)" data-language-autonym="Bahasa Melayu" data-language-local-name="มาเลย์" class="interlanguage-link-target"><span>Bahasa Melayu</span></a></li><li class="interlanguage-link interwiki-myv mw-list-item"><a href="https://myv.wikipedia.org/wiki/21_(%D0%BB%D0%BE%D0%B2%D0%BE%D0%BC%D0%B0_%D0%B2%D0%B0%D0%BB)" title="21 (ловома вал) – เอียร์ซยา" lang="myv" hreflang="myv" data-title="21 (ловома вал)" data-language-autonym="Эрзянь" data-language-local-name="เอียร์ซยา" class="interlanguage-link-target"><span>Эрзянь</span></a></li><li class="interlanguage-link interwiki-mzn mw-list-item"><a href="https://mzn.wikipedia.org/wiki/%DB%B2%DB%B1_(%D8%B9%D8%AF%D8%AF)" title="۲۱ (عدد) – มาซันดารานี" lang="mzn" hreflang="mzn" data-title="۲۱ (عدد)" data-language-autonym="مازِرونی" data-language-local-name="มาซันดารานี" class="interlanguage-link-target"><span>مازِرونی</span></a></li><li class="interlanguage-link interwiki-nah mw-list-item"><a href="https://nah.wikipedia.org/wiki/C%C4%93mp%C5%8Dhualonc%C4%93" title="Cēmpōhualoncē – Nahuatl" lang="nah" hreflang="nah" data-title="Cēmpōhualoncē" data-language-autonym="Nāhuatl" data-language-local-name="Nahuatl" class="interlanguage-link-target"><span>Nāhuatl</span></a></li><li class="interlanguage-link interwiki-nap mw-list-item"><a href="https://nap.wikipedia.org/wiki/Vint%C3%B9ne" title="Vintùne – นาโปลี" lang="nap" hreflang="nap" data-title="Vintùne" data-language-autonym="Napulitano" data-language-local-name="นาโปลี" class="interlanguage-link-target"><span>Napulitano</span></a></li><li class="interlanguage-link interwiki-nl mw-list-item"><a href="https://nl.wikipedia.org/wiki/21_(getal)" title="21 (getal) – ดัตช์" lang="nl" hreflang="nl" data-title="21 (getal)" data-language-autonym="Nederlands" data-language-local-name="ดัตช์" class="interlanguage-link-target"><span>Nederlands</span></a></li><li class="interlanguage-link interwiki-nn mw-list-item"><a href="https://nn.wikipedia.org/wiki/Talet_21" title="Talet 21 – นอร์เวย์นีนอสก์" lang="nn" hreflang="nn" data-title="Talet 21" data-language-autonym="Norsk nynorsk" data-language-local-name="นอร์เวย์นีนอสก์" class="interlanguage-link-target"><span>Norsk nynorsk</span></a></li><li class="interlanguage-link interwiki-no mw-list-item"><a href="https://no.wikipedia.org/wiki/21_(tall)" title="21 (tall) – นอร์เวย์บุคมอล" lang="nb" hreflang="nb" data-title="21 (tall)" data-language-autonym="Norsk bokmål" data-language-local-name="นอร์เวย์บุคมอล" class="interlanguage-link-target"><span>Norsk bokmål</span></a></li><li class="interlanguage-link interwiki-nso mw-list-item"><a href="https://nso.wikipedia.org/wiki/21_(nomoro)" title="21 (nomoro) – โซโทเหนือ" lang="nso" hreflang="nso" data-title="21 (nomoro)" data-language-autonym="Sesotho sa Leboa" data-language-local-name="โซโทเหนือ" class="interlanguage-link-target"><span>Sesotho sa Leboa</span></a></li><li class="interlanguage-link interwiki-pl mw-list-item"><a href="https://pl.wikipedia.org/wiki/21_(liczba)" title="21 (liczba) – โปแลนด์" lang="pl" hreflang="pl" data-title="21 (liczba)" data-language-autonym="Polski" data-language-local-name="โปแลนด์" class="interlanguage-link-target"><span>Polski</span></a></li><li class="interlanguage-link interwiki-pnb mw-list-item"><a href="https://pnb.wikipedia.org/wiki/21" title="21 – Western Punjabi" lang="pnb" hreflang="pnb" data-title="21" data-language-autonym="پنجابی" data-language-local-name="Western Punjabi" class="interlanguage-link-target"><span>پنجابی</span></a></li><li class="interlanguage-link interwiki-ps mw-list-item"><a href="https://ps.wikipedia.org/wiki/%DB%B2%DB%B1_(%D8%B9%D8%AF%D8%AF)" title="۲۱ (عدد) – พัชโต" lang="ps" hreflang="ps" data-title="۲۱ (عدد)" data-language-autonym="پښتو" data-language-local-name="พัชโต" class="interlanguage-link-target"><span>پښتو</span></a></li><li class="interlanguage-link interwiki-pt badge-Q70893996 mw-list-item" title=""><a href="https://pt.wikipedia.org/wiki/Vinte_e_um" title="Vinte e um – โปรตุเกส" lang="pt" hreflang="pt" data-title="Vinte e um" data-language-autonym="Português" data-language-local-name="โปรตุเกส" class="interlanguage-link-target"><span>Português</span></a></li><li class="interlanguage-link interwiki-rn mw-list-item"><a href="https://rn.wikipedia.org/wiki/Mirongo_ibiri_na_rimwe" title="Mirongo ibiri na rimwe – บุรุนดี" lang="rn" hreflang="rn" data-title="Mirongo ibiri na rimwe" data-language-autonym="Ikirundi" data-language-local-name="บุรุนดี" class="interlanguage-link-target"><span>Ikirundi</span></a></li><li class="interlanguage-link interwiki-ro mw-list-item"><a href="https://ro.wikipedia.org/wiki/21_(num%C4%83r)" title="21 (număr) – โรมาเนีย" lang="ro" hreflang="ro" data-title="21 (număr)" data-language-autonym="Română" data-language-local-name="โรมาเนีย" class="interlanguage-link-target"><span>Română</span></a></li><li class="interlanguage-link interwiki-ru mw-list-item"><a href="https://ru.wikipedia.org/wiki/21_(%D1%87%D0%B8%D1%81%D0%BB%D0%BE)" title="21 (число) – รัสเซีย" lang="ru" hreflang="ru" data-title="21 (число)" data-language-autonym="Русский" data-language-local-name="รัสเซีย" class="interlanguage-link-target"><span>Русский</span></a></li><li class="interlanguage-link interwiki-simple mw-list-item"><a href="https://simple.wikipedia.org/wiki/21_(number)" title="21 (number) – Simple English" lang="en-simple" hreflang="en-simple" data-title="21 (number)" data-language-autonym="Simple English" data-language-local-name="Simple English" class="interlanguage-link-target"><span>Simple English</span></a></li><li class="interlanguage-link interwiki-sl mw-list-item"><a href="https://sl.wikipedia.org/wiki/21_(%C5%A1tevilo)" title="21 (število) – สโลวีเนีย" lang="sl" hreflang="sl" data-title="21 (število)" data-language-autonym="Slovenščina" data-language-local-name="สโลวีเนีย" class="interlanguage-link-target"><span>Slovenščina</span></a></li><li class="interlanguage-link interwiki-sm mw-list-item"><a href="https://sm.wikipedia.org/wiki/21_(numera)" title="21 (numera) – ซามัว" lang="sm" hreflang="sm" data-title="21 (numera)" data-language-autonym="Gagana Samoa" data-language-local-name="ซามัว" class="interlanguage-link-target"><span>Gagana Samoa</span></a></li><li class="interlanguage-link interwiki-so mw-list-item"><a href="https://so.wikipedia.org/wiki/21_(tiro)" title="21 (tiro) – โซมาลี" lang="so" hreflang="so" data-title="21 (tiro)" data-language-autonym="Soomaaliga" data-language-local-name="โซมาลี" class="interlanguage-link-target"><span>Soomaaliga</span></a></li><li class="interlanguage-link interwiki-sr mw-list-item"><a href="https://sr.wikipedia.org/wiki/21_(%D0%B1%D1%80%D0%BE%D1%98)" title="21 (број) – เซอร์เบีย" lang="sr" hreflang="sr" data-title="21 (број)" data-language-autonym="Српски / srpski" data-language-local-name="เซอร์เบีย" class="interlanguage-link-target"><span>Српски / srpski</span></a></li><li class="interlanguage-link interwiki-srn mw-list-item"><a href="https://srn.wikipedia.org/wiki/Numro_21" title="Numro 21 – สรานานตองโก" lang="srn" hreflang="srn" data-title="Numro 21" data-language-autonym="Sranantongo" data-language-local-name="สรานานตองโก" class="interlanguage-link-target"><span>Sranantongo</span></a></li><li class="interlanguage-link interwiki-sv mw-list-item"><a href="https://sv.wikipedia.org/wiki/21_(tal)" title="21 (tal) – สวีเดน" lang="sv" hreflang="sv" data-title="21 (tal)" data-language-autonym="Svenska" data-language-local-name="สวีเดน" class="interlanguage-link-target"><span>Svenska</span></a></li><li class="interlanguage-link interwiki-sw mw-list-item"><a href="https://sw.wikipedia.org/wiki/Ishirini_na_moja" title="Ishirini na moja – สวาฮีลี" lang="sw" hreflang="sw" data-title="Ishirini na moja" data-language-autonym="Kiswahili" data-language-local-name="สวาฮีลี" class="interlanguage-link-target"><span>Kiswahili</span></a></li><li class="interlanguage-link interwiki-tr mw-list-item"><a href="https://tr.wikipedia.org/wiki/21_(say%C4%B1)" title="21 (sayı) – ตุรกี" lang="tr" hreflang="tr" data-title="21 (sayı)" data-language-autonym="Türkçe" data-language-local-name="ตุรกี" class="interlanguage-link-target"><span>Türkçe</span></a></li><li class="interlanguage-link interwiki-tt mw-list-item"><a href="https://tt.wikipedia.org/wiki/21_(%D1%81%D0%B0%D0%BD)" title="21 (сан) – ตาตาร์" lang="tt" hreflang="tt" data-title="21 (сан)" data-language-autonym="Татарча / tatarça" data-language-local-name="ตาตาร์" class="interlanguage-link-target"><span>Татарча / tatarça</span></a></li><li class="interlanguage-link interwiki-tyv mw-list-item"><a href="https://tyv.wikipedia.org/wiki/21" title="21 – ตูวา" lang="tyv" hreflang="tyv" data-title="21" data-language-autonym="Тыва дыл" data-language-local-name="ตูวา" class="interlanguage-link-target"><span>Тыва дыл</span></a></li><li class="interlanguage-link interwiki-uk mw-list-item"><a href="https://uk.wikipedia.org/wiki/21_(%D1%87%D0%B8%D1%81%D0%BB%D0%BE)" title="21 (число) – ยูเครน" lang="uk" hreflang="uk" data-title="21 (число)" data-language-autonym="Українська" data-language-local-name="ยูเครน" class="interlanguage-link-target"><span>Українська</span></a></li><li class="interlanguage-link interwiki-ur mw-list-item"><a href="https://ur.wikipedia.org/wiki/21_(%D8%B9%D8%AF%D8%AF)" title="21 (عدد) – อูรดู" lang="ur" hreflang="ur" data-title="21 (عدد)" data-language-autonym="اردو" data-language-local-name="อูรดู" class="interlanguage-link-target"><span>اردو</span></a></li><li class="interlanguage-link interwiki-uz mw-list-item"><a href="https://uz.wikipedia.org/wiki/21_(son)" title="21 (son) – อุซเบก" lang="uz" hreflang="uz" data-title="21 (son)" data-language-autonym="Oʻzbekcha / ўзбекча" data-language-local-name="อุซเบก" class="interlanguage-link-target"><span>Oʻzbekcha / ўзбекча</span></a></li><li class="interlanguage-link interwiki-vep mw-list-item"><a href="https://vep.wikipedia.org/wiki/21_(lugu)" title="21 (lugu) – เวปส์" lang="vep" hreflang="vep" data-title="21 (lugu)" data-language-autonym="Vepsän kel’" data-language-local-name="เวปส์" class="interlanguage-link-target"><span>Vepsän kel’</span></a></li><li class="interlanguage-link interwiki-vi mw-list-item"><a href="https://vi.wikipedia.org/wiki/21_(s%E1%BB%91)" title="21 (số) – เวียดนาม" lang="vi" hreflang="vi" data-title="21 (số)" data-language-autonym="Tiếng Việt" data-language-local-name="เวียดนาม" class="interlanguage-link-target"><span>Tiếng Việt</span></a></li><li class="interlanguage-link interwiki-vls mw-list-item"><a href="https://vls.wikipedia.org/wiki/21_(getal)" title="21 (getal) – เฟลมิชตะวันตก" lang="vls" hreflang="vls" data-title="21 (getal)" data-language-autonym="West-Vlams" data-language-local-name="เฟลมิชตะวันตก" class="interlanguage-link-target"><span>West-Vlams</span></a></li><li class="interlanguage-link interwiki-war mw-list-item"><a href="https://war.wikipedia.org/wiki/21_(ihap)" title="21 (ihap) – วาเรย์" lang="war" hreflang="war" data-title="21 (ihap)" data-language-autonym="Winaray" data-language-local-name="วาเรย์" class="interlanguage-link-target"><span>Winaray</span></a></li><li class="interlanguage-link interwiki-wuu mw-list-item"><a href="https://wuu.wikipedia.org/wiki/21" title="21 – จีนอู๋" lang="wuu" hreflang="wuu" data-title="21" data-language-autonym="吴语" data-language-local-name="จีนอู๋" class="interlanguage-link-target"><span>吴语</span></a></li><li class="interlanguage-link interwiki-xh mw-list-item"><a href="https://xh.wikipedia.org/wiki/Amashumi_amabini_ananye" title="Amashumi amabini ananye – คะห์โอซา" lang="xh" hreflang="xh" data-title="Amashumi amabini ananye" data-language-autonym="IsiXhosa" data-language-local-name="คะห์โอซา" class="interlanguage-link-target"><span>IsiXhosa</span></a></li><li class="interlanguage-link interwiki-yi mw-list-item"><a href="https://yi.wikipedia.org/wiki/21_(%D7%A0%D7%95%D7%9E%D7%A2%D7%A8)" title="21 (נומער) – ยิดดิช" lang="yi" hreflang="yi" data-title="21 (נומער)" data-language-autonym="ייִדיש" data-language-local-name="ยิดดิช" class="interlanguage-link-target"><span>ייִדיש</span></a></li><li class="interlanguage-link interwiki-za mw-list-item"><a href="https://za.wikipedia.org/wiki/21" title="21 – จ้วง" lang="za" hreflang="za" data-title="21" data-language-autonym="Vahcuengh" data-language-local-name="จ้วง" class="interlanguage-link-target"><span>Vahcuengh</span></a></li><li class="interlanguage-link interwiki-zh mw-list-item"><a href="https://zh.wikipedia.org/wiki/21" title="21 – จีน" lang="zh" hreflang="zh" data-title="21" data-language-autonym="中文" data-language-local-name="จีน" class="interlanguage-link-target"><span>中文</span></a></li><li class="interlanguage-link interwiki-zh-min-nan mw-list-item"><a href="https://zh-min-nan.wikipedia.org/wiki/21" title="21 – จีนมินหนาน" lang="nan" hreflang="nan" data-title="21" data-language-autonym="閩南語 / Bân-lâm-gú" data-language-local-name="จีนมินหนาน" class="interlanguage-link-target"><span>閩南語 / Bân-lâm-gú</span></a></li><li class="interlanguage-link interwiki-zh-yue mw-list-item"><a href="https://zh-yue.wikipedia.org/wiki/21" title="21 – กวางตุ้ง" lang="yue" hreflang="yue" data-title="21" data-language-autonym="粵語" data-language-local-name="กวางตุ้ง" class="interlanguage-link-target"><span>粵語</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/Q712477#sitelinks-wikipedia" title="แก้ไขลิงก์ข้ามภาษา" class="wbc-editpage">แก้ไขลิงก์</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="เนมสเปซ"> <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/21" title="ดูหน้าเนื้อหา [c]" accesskey="c"><span>บทความ</span></a></li><li id="ca-talk" class="new vector-tab-noicon mw-list-item"><a href="/w/index.php?title=%E0%B8%9E%E0%B8%B9%E0%B8%94%E0%B8%84%E0%B8%B8%E0%B8%A2:21&action=edit&redlink=1" rel="discussion" class="new" title="อภิปรายเกี่ยวกับหน้าเนื้อหา (ไม่มีหน้านี้) [t]" accesskey="t"><span>อภิปราย</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="เปลี่ยนรูปแบบภาษา" > <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">ไทย</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="ดู"> <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/21"><span>อ่าน</span></a></li><li id="ca-edit" class="vector-tab-noicon mw-list-item"><a href="/w/index.php?title=21&action=edit" title="แก้ไขรหัสต้นฉบับของหน้านี้ [e]" accesskey="e"><span>แก้ไข</span></a></li><li id="ca-history" class="vector-tab-noicon mw-list-item"><a href="/w/index.php?title=21&action=history" title="แก้ไขเก่าของหน้านี้ [h]" accesskey="h"><span>ดูประวัติ</span></a></li> </ul> </div> </div> </nav> <nav class="vector-page-tools-landmark" aria-label="หน้าเครื่องมือ"> <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="เครื่องมือ" > <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">เครื่องมือ</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">เครื่องมือ</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-page-tools.pin">ย้ายเมนูไปที่แถบด้านข้าง</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-page-tools.unpin">ซ่อน</button> </div> <div id="p-cactions" class="vector-menu mw-portlet mw-portlet-cactions emptyPortlet vector-has-collapsible-items" title="ตัวเลือกเพิ่มเติม" > <div class="vector-menu-heading"> การกระทำ </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/21"><span>อ่าน</span></a></li><li id="ca-more-edit" class="vector-more-collapsible-item mw-list-item"><a href="/w/index.php?title=21&action=edit" title="แก้ไขรหัสต้นฉบับของหน้านี้ [e]" accesskey="e"><span>แก้ไข</span></a></li><li id="ca-more-history" class="vector-more-collapsible-item mw-list-item"><a href="/w/index.php?title=21&action=history"><span>ดูประวัติ</span></a></li> </ul> </div> </div> <div id="p-tb" class="vector-menu mw-portlet mw-portlet-tb" > <div class="vector-menu-heading"> ทั่วไป </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="t-whatlinkshere" class="mw-list-item"><a href="/wiki/%E0%B8%9E%E0%B8%B4%E0%B9%80%E0%B8%A8%E0%B8%A9:%E0%B8%9A%E0%B8%97%E0%B8%84%E0%B8%A7%E0%B8%B2%E0%B8%A1%E0%B8%97%E0%B8%B5%E0%B9%88%E0%B9%82%E0%B8%A2%E0%B8%87%E0%B8%A1%E0%B8%B2/21" title="รายการหน้าวิกิทุกหน้าที่ลิงก์มาที่นี่ [j]" accesskey="j"><span>หน้าที่ลิงก์มา</span></a></li><li id="t-recentchangeslinked" class="mw-list-item"><a href="/wiki/%E0%B8%9E%E0%B8%B4%E0%B9%80%E0%B8%A8%E0%B8%A9:%E0%B8%81%E0%B8%B2%E0%B8%A3%E0%B8%9B%E0%B8%A3%E0%B8%B1%E0%B8%9A%E0%B8%9B%E0%B8%A3%E0%B8%B8%E0%B8%87%E0%B8%97%E0%B8%B5%E0%B9%88%E0%B9%82%E0%B8%A2%E0%B8%87%E0%B8%A1%E0%B8%B2/21" rel="nofollow" title="รายการเปลี่ยนแปลงล่าสุดในหน้าที่ลิงก์จากหน้านี้ [k]" accesskey="k"><span>การเปลี่ยนแปลงที่เกี่ยวโยง</span></a></li><li id="t-upload" class="mw-list-item"><a href="/wiki/%E0%B8%A7%E0%B8%B4%E0%B8%81%E0%B8%B4%E0%B8%9E%E0%B8%B5%E0%B9%80%E0%B8%94%E0%B8%B5%E0%B8%A2:%E0%B8%AD%E0%B8%B1%E0%B8%9B%E0%B9%82%E0%B8%AB%E0%B8%A5%E0%B8%94" title="อัปโหลดไฟล์ [u]" accesskey="u"><span>อัปโหลดไฟล์</span></a></li><li id="t-specialpages" class="mw-list-item"><a href="/wiki/%E0%B8%9E%E0%B8%B4%E0%B9%80%E0%B8%A8%E0%B8%A9:%E0%B8%AB%E0%B8%99%E0%B9%89%E0%B8%B2%E0%B8%9E%E0%B8%B4%E0%B9%80%E0%B8%A8%E0%B8%A9" title="รายการหน้าพิเศษทั้งหมด [q]" accesskey="q"><span>หน้าพิเศษ</span></a></li><li id="t-permalink" class="mw-list-item"><a href="/w/index.php?title=21&oldid=7391731" title="ลิงก์ถาวรมารุ่นนี้ของหน้านี้"><span>ลิงก์ถาวร</span></a></li><li id="t-info" class="mw-list-item"><a href="/w/index.php?title=21&action=info" title="ข้อมูลเพิ่มเติมเกี่ยวกับหน้านี้"><span>สารสนเทศหน้า</span></a></li><li id="t-cite" class="mw-list-item"><a href="/w/index.php?title=%E0%B8%9E%E0%B8%B4%E0%B9%80%E0%B8%A8%E0%B8%A9:%E0%B8%AD%E0%B9%89%E0%B8%B2%E0%B8%87%E0%B8%AD%E0%B8%B4%E0%B8%87&page=21&id=7391731&wpFormIdentifier=titleform" title="สารสนเทศเกี่ยวกับวิธีการอ้างอิงหน้านี้"><span>อ้างอิงบทความนี้</span></a></li><li id="t-urlshortener" class="mw-list-item"><a href="/w/index.php?title=%E0%B8%9E%E0%B8%B4%E0%B9%80%E0%B8%A8%E0%B8%A9:UrlQ%C4%B1sald%C4%B1c%C4%B1s%C4%B1&url=https%3A%2F%2Fth.wikipedia.org%2Fwiki%2F21"><span>รับยูอาร์แอลแบบสั้น</span></a></li><li id="t-urlshortener-qrcode" class="mw-list-item"><a href="/w/index.php?title=%E0%B8%9E%E0%B8%B4%E0%B9%80%E0%B8%A8%E0%B8%A9:QrKodu&url=https%3A%2F%2Fth.wikipedia.org%2Fwiki%2F21"><span>ดาวน์โหลดคิวอาร์โค้ด</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"> พิมพ์/ส่งออก </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="coll-create_a_book" class="mw-list-item"><a href="/w/index.php?title=%E0%B8%9E%E0%B8%B4%E0%B9%80%E0%B8%A8%E0%B8%A9:%E0%B8%AB%E0%B8%99%E0%B8%B1%E0%B8%87%E0%B8%AA%E0%B8%B7%E0%B8%AD&bookcmd=book_creator&referer=21"><span>สร้างหนังสือ</span></a></li><li id="coll-download-as-rl" class="mw-list-item"><a href="/w/index.php?title=%E0%B8%9E%E0%B8%B4%E0%B9%80%E0%B8%A8%E0%B8%A9:DownloadAsPdf&page=21&action=show-download-screen"><span>ดาวน์โหลดเป็น PDF</span></a></li><li id="t-print" class="mw-list-item"><a href="/w/index.php?title=21&printable=yes" title="รุ่นที่พร้อมพิมพ์ของหน้านี้ [p]" accesskey="p"><span>รุ่นพร้อมพิมพ์</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"> ในโครงการอื่น </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:21_(number)" hreflang="en"><span>วิกิมีเดียคอมมอนส์</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/Q712477" title="ลิงก์ไปยังสิ่งนี้ในคลังซึ่งเชื่อมโยงข้อมูลต่าง ๆ เข้าด้วยกัน [g]" accesskey="g"><span>สิ่งนี้ในวิกิสนเทศ</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="หน้าเครื่องมือ"> <div id="vector-page-tools-pinned-container" class="vector-pinned-container"> </div> </nav> <nav class="vector-appearance-landmark" aria-label="หน้าตา"> <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">หน้าตา</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-appearance.pin">ย้ายเมนูไปที่แถบด้านข้าง</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-appearance.unpin">ซ่อน</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> <div id="siteSub" class="noprint">จากวิกิพีเดีย สารานุกรมเสรี</div> </div> <div id="contentSub"><div id="mw-content-subtitle"></div></div> <div id="mw-content-text" class="mw-body-content"><div class="mw-content-ltr mw-parser-output" lang="th" dir="ltr"><table class="infobox" style="width:22em;line-height: 1.5em"><tbody><tr><th colspan="2" style="text-align:center;font-size:125%;font-weight:bold;font-size: 150%"><table style="width:100%; margin:0"><tbody><tr> <td style="width:15%; text-align:left; white-space: nowrap; font-size:smaller"><span class="Unicode">←</span> 20</td> <td style="width:70%; padding-left:1em; padding-right:1em">21</td> <td style="width:15%; text-align:right; white-space: nowrap; font-size:smaller">22 <span class="Unicode">→</span></td> </tr></tbody></table></th></tr><tr><td colspan="2" style="text-align:center;font-size:100%;"><div style="text-align:center;font-size:smaller;white-space:nowrap;"> <a href="/wiki/19" title="19"><span class="Unicode">←</span></a> <a href="/wiki/20" title="20">20</a> <a class="mw-selflink selflink">21</a> <a href="/wiki/22" title="22">22</a> <a href="/wiki/23" title="23">23</a> <a href="/wiki/24" title="24">24</a> <a href="/wiki/25" title="25">25</a> <a href="/wiki/26" title="26">26</a> <a href="/wiki/27" title="27">27</a> <a href="/wiki/28" title="28">28</a> <a href="/wiki/29" title="29">29</a> <a href="/wiki/30" title="30"><span class="Unicode">→</span></a></div><div style="text-align:center;font-size:smaller;white-space:nowrap;"> <a href="/wiki/%E0%B8%A3%E0%B8%B2%E0%B8%A2%E0%B8%8A%E0%B8%B7%E0%B9%88%E0%B8%AD%E0%B8%88%E0%B8%B3%E0%B8%99%E0%B8%A7%E0%B8%99" title="รายชื่อจำนวน">รายชื่อจำนวน</a> — <a href="/wiki/%E0%B8%88%E0%B8%B3%E0%B8%99%E0%B8%A7%E0%B8%99%E0%B9%80%E0%B8%95%E0%B9%87%E0%B8%A1" title="จำนวนเต็ม">จำนวนเต็ม</a> </div><div style="text-align:center;font-size:smaller;white-space:nowrap;"> <a href="/wiki/%E0%B8%88%E0%B8%B3%E0%B8%99%E0%B8%A7%E0%B8%99%E0%B8%A5%E0%B8%9A" class="mw-redirect" title="จำนวนลบ"><span class="Unicode">←</span></a> <a href="/wiki/0" title="0">0</a> <a href="/wiki/10" title="10">10</a> <a href="/wiki/20" title="20">20</a> <a href="/wiki/30" title="30">30</a> <a href="/wiki/40" title="40">40</a> <a href="/wiki/50" title="50">50</a> <a href="/wiki/60" title="60">60</a> <a href="/wiki/70" title="70">70</a> <a href="/wiki/80" title="80">80</a> <a href="/wiki/90" title="90">90</a> <a href="/wiki/100" title="100"><span class="Unicode">→</span></a></div></td></tr><tr><th scope="row" style="font-weight:normal"><a href="/w/index.php?title=%E0%B8%88%E0%B8%B3%E0%B8%99%E0%B8%A7%E0%B8%99%E0%B9%80%E0%B8%8A%E0%B8%B4%E0%B8%87%E0%B8%81%E0%B8%B2%E0%B8%A3%E0%B8%99%E0%B8%B1%E0%B8%9A&action=edit&redlink=1" class="new" title="จำนวนเชิงการนับ (ไม่มีหน้านี้)">จำนวนเชิงการนับ</a></th><td>ยี่สิบเอ็ด</td></tr><tr><th scope="row" style="font-weight:normal"><a href="/wiki/%E0%B8%88%E0%B8%B3%E0%B8%99%E0%B8%A7%E0%B8%99%E0%B9%80%E0%B8%8A%E0%B8%B4%E0%B8%87%E0%B8%AD%E0%B8%B1%E0%B8%99%E0%B8%94%E0%B8%B1%E0%B8%9A%E0%B8%97%E0%B8%B5%E0%B9%88" title="จำนวนเชิงอันดับที่">จำนวนเชิงอันดับที่</a></th><td>21st (ที่ยี่สิบเอ็ด)</td></tr><tr><th scope="row" style="font-weight:normal"><a href="/wiki/%E0%B8%81%E0%B8%B2%E0%B8%A3%E0%B9%81%E0%B8%A2%E0%B8%81%E0%B8%95%E0%B8%B1%E0%B8%A7%E0%B8%9B%E0%B8%A3%E0%B8%B0%E0%B8%81%E0%B8%AD%E0%B8%9A" title="การแยกตัวประกอบ">ตัวประกอบ</a></th><td><span class="texhtml" style="font-size:165%">3 · 7 </span></td></tr><tr><th scope="row" style="font-weight:normal"><a href="/wiki/%E0%B9%80%E0%B8%A5%E0%B8%82%E0%B9%84%E0%B8%97%E0%B8%A2" class="mw-redirect" title="เลขไทย">เลขไทย</a></th><td>๒๑</td></tr><tr><th scope="row" style="font-weight:normal"><a href="/wiki/%E0%B9%80%E0%B8%A5%E0%B8%82%E0%B9%82%E0%B8%A3%E0%B8%A1%E0%B8%B1%E0%B8%99" class="mw-redirect" title="เลขโรมัน">เลขโรมัน</a></th><td>XXI</td></tr><tr><th scope="row" style="font-weight:normal"><a href="/wiki/%E0%B9%80%E0%B8%A5%E0%B8%82%E0%B8%88%E0%B8%B5%E0%B8%99" class="mw-redirect" title="เลขจีน">เลขจีน</a></th><td><span title="ข้อความภาษาจีน"><span lang="zh">二十一</span></span></td></tr><tr><th scope="row" style="font-weight:normal"><a href="/wiki/%E0%B9%80%E0%B8%A5%E0%B8%82%E0%B8%90%E0%B8%B2%E0%B8%99%E0%B8%AA%E0%B8%AD%E0%B8%87" title="เลขฐานสอง">ฐานสอง</a></th><td>10101</td></tr><tr><th scope="row" style="font-weight:normal"><a href="/wiki/%E0%B9%80%E0%B8%A5%E0%B8%82%E0%B8%90%E0%B8%B2%E0%B8%99%E0%B8%AA%E0%B8%B2%E0%B8%A1" title="เลขฐานสาม">ฐานสาม</a></th><td>210</td></tr><tr><th scope="row" style="font-weight:normal"><a href="/wiki/%E0%B9%80%E0%B8%A5%E0%B8%82%E0%B8%90%E0%B8%B2%E0%B8%99%E0%B8%AA%E0%B8%B5%E0%B9%88" title="เลขฐานสี่">ฐานสี่</a></th><td>111</td></tr><tr><th scope="row" style="font-weight:normal"><a href="/wiki/%E0%B9%80%E0%B8%A5%E0%B8%82%E0%B8%90%E0%B8%B2%E0%B8%99%E0%B8%AB%E0%B9%89%E0%B8%B2" title="เลขฐานห้า">ฐานห้า</a></th><td>41</td></tr><tr><th scope="row" style="font-weight:normal"><a href="/wiki/%E0%B9%80%E0%B8%A5%E0%B8%82%E0%B8%90%E0%B8%B2%E0%B8%99%E0%B8%AB%E0%B8%81" title="เลขฐานหก">ฐานหก</a></th><td>33</td></tr><tr><th scope="row" style="font-weight:normal"><a href="/wiki/%E0%B9%80%E0%B8%A5%E0%B8%82%E0%B8%90%E0%B8%B2%E0%B8%99%E0%B9%81%E0%B8%9B%E0%B8%94" title="เลขฐานแปด">ฐานแปด</a></th><td>25</td></tr><tr><th scope="row" style="font-weight:normal"><a href="/wiki/%E0%B9%80%E0%B8%A5%E0%B8%82%E0%B8%90%E0%B8%B2%E0%B8%99%E0%B8%AA%E0%B8%B4%E0%B8%9A%E0%B8%AA%E0%B8%AD%E0%B8%87" title="เลขฐานสิบสอง">ฐานสิบสอง</a></th><td>19</td></tr><tr><th scope="row" style="font-weight:normal"><a href="/wiki/%E0%B9%80%E0%B8%A5%E0%B8%82%E0%B8%90%E0%B8%B2%E0%B8%99%E0%B8%AA%E0%B8%B4%E0%B8%9A%E0%B8%AB%E0%B8%81" title="เลขฐานสิบหก">ฐานสิบหก</a></th><td>15</td></tr><tr><th scope="row" style="font-weight:normal"><a href="/wiki/%E0%B9%80%E0%B8%A5%E0%B8%82%E0%B8%90%E0%B8%B2%E0%B8%99%E0%B8%A2%E0%B8%B5%E0%B9%88%E0%B8%AA%E0%B8%B4%E0%B8%9A" title="เลขฐานยี่สิบ">ฐานยี่สิบ</a></th><td>11</td></tr><tr><th scope="row" style="font-weight:normal"><a href="/wiki/%E0%B9%80%E0%B8%A5%E0%B8%82%E0%B8%90%E0%B8%B2%E0%B8%99%E0%B8%AA%E0%B8%B2%E0%B8%A1%E0%B8%AA%E0%B8%B4%E0%B8%9A%E0%B8%AB%E0%B8%81" title="เลขฐานสามสิบหก">ฐานสามสิบหก</a></th><td>L</td></tr></tbody></table> <p><b>21</b> (<b>ยี่สิบเอ็ด</b>) เป็น<a href="/wiki/%E0%B8%88%E0%B8%B3%E0%B8%99%E0%B8%A7%E0%B8%99%E0%B8%98%E0%B8%A3%E0%B8%A3%E0%B8%A1%E0%B8%8A%E0%B8%B2%E0%B8%95%E0%B8%B4" title="จำนวนธรรมชาติ">จำนวนธรรมชาติ</a>ที่อยู่ถัดจาก <a href="/wiki/20" title="20">20</a> (ยี่สิบ) และอยู่ก่อนหน้า <a href="/wiki/22" title="22">22</a> (ยี่สิบสอง) </p> <div class="mw-heading mw-heading2"><h2 id="คำเติมนำหน้า"><span id=".E0.B8.84.E0.B8.B3.E0.B9.80.E0.B8.95.E0.B8.B4.E0.B8.A1.E0.B8.99.E0.B8.B3.E0.B8.AB.E0.B8.99.E0.B9.89.E0.B8.B2"></span>คำเติมนำหน้า</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=21&action=edit&section=1" title="แก้ไขส่วน: คำเติมนำหน้า"><span>แก้</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a href="/wiki/%E0%B8%A0%E0%B8%B2%E0%B8%A9%E0%B8%B2%E0%B8%81%E0%B8%A3%E0%B8%B5%E0%B8%81" title="ภาษากรีก">ภาษากรีก</a> - <a href="https://en.wiktionary.org/wiki/henicosa-" class="extiw" title="wiktionary:henicosa-">henicosa-</a></li> <li><a href="/wiki/%E0%B8%A0%E0%B8%B2%E0%B8%A9%E0%B8%B2%E0%B8%A5%E0%B8%B0%E0%B8%95%E0%B8%B4%E0%B8%99" title="ภาษาละติน">ภาษาละติน</a> - <a href="https://en.wiktionary.org/wiki/unviginti-" class="extiw" title="wiktionary:unviginti-">unviginti-</a></li></ul> <div class="mw-heading mw-heading2"><h2 id="ความหมาย"><span id=".E0.B8.84.E0.B8.A7.E0.B8.B2.E0.B8.A1.E0.B8.AB.E0.B8.A1.E0.B8.B2.E0.B8.A2"></span>ความหมาย</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=21&action=edit&section=2" title="แก้ไขส่วน: ความหมาย"><span>แก้</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li>21 เป็น<a href="/wiki/%E0%B9%80%E0%B8%A5%E0%B8%82%E0%B8%AD%E0%B8%B0%E0%B8%95%E0%B8%AD%E0%B8%A1" title="เลขอะตอม">เลขอะตอม</a>ของ <a href="/wiki/%E0%B8%AA%E0%B9%81%E0%B8%84%E0%B8%99%E0%B9%80%E0%B8%94%E0%B8%B5%E0%B8%A2%E0%B8%A1" class="mw-redirect" title="สแคนเดียม">สแคนเดียม</a></li></ul> <div class="mw-heading mw-heading2"><h2 id="ในทางคณิตศาสตร์"><span id=".E0.B9.83.E0.B8.99.E0.B8.97.E0.B8.B2.E0.B8.87.E0.B8.84.E0.B8.93.E0.B8.B4.E0.B8.95.E0.B8.A8.E0.B8.B2.E0.B8.AA.E0.B8.95.E0.B8.A3.E0.B9.8C"></span>ในทางคณิตศาสตร์</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=21&action=edit&section=3" title="แก้ไขส่วน: ในทางคณิตศาสตร์"><span>แก้</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li>21 เป็น<a href="/wiki/%E0%B8%88%E0%B8%B3%E0%B8%99%E0%B8%A7%E0%B8%99%E0%B8%9F%E0%B8%B5%E0%B9%82%E0%B8%9A%E0%B8%99%E0%B8%B1%E0%B8%8A%E0%B8%8A%E0%B8%B5" title="จำนวนฟีโบนัชชี">จำนวนฟีโบนัชชี</a>ลำดับที่แปด</li></ul>    </div><noscript><img src="https://login.wikimedia.org/wiki/Special:CentralAutoLogin/start?useformat=desktop&type=1x1&usesul3=0" alt="" width="1" height="1" style="border: none; position: absolute;"></noscript> <div class="printfooter" data-nosnippet="">เข้าถึงจาก "<a dir="ltr" href="https://th.wikipedia.org/w/index.php?title=21&oldid=7391731">https://th.wikipedia.org/w/index.php?title=21&oldid=7391731</a>"</div></div> <div id="catlinks" class="catlinks" data-mw="interface"><div id="mw-normal-catlinks" class="mw-normal-catlinks"><a href="/wiki/%E0%B8%9E%E0%B8%B4%E0%B9%80%E0%B8%A8%E0%B8%A9:%E0%B8%AB%E0%B8%A1%E0%B8%A7%E0%B8%94%E0%B8%AB%E0%B8%A1%E0%B8%B9%E0%B9%88" title="พิเศษ:หมวดหมู่">หมวดหมู่</a>: <ul><li><a href="/wiki/%E0%B8%AB%E0%B8%A1%E0%B8%A7%E0%B8%94%E0%B8%AB%E0%B8%A1%E0%B8%B9%E0%B9%88:%E0%B8%88%E0%B8%B3%E0%B8%99%E0%B8%A7%E0%B8%99%E0%B9%80%E0%B8%95%E0%B9%87%E0%B8%A1" title="หมวดหมู่:จำนวนเต็ม">จำนวนเต็ม</a></li></ul></div><div id="mw-hidden-catlinks" class="mw-hidden-catlinks mw-hidden-cats-hidden">หมวดหมู่ที่ซ่อนอยู่: <ul><li><a href="/wiki/%E0%B8%AB%E0%B8%A1%E0%B8%A7%E0%B8%94%E0%B8%AB%E0%B8%A1%E0%B8%B9%E0%B9%88:%E0%B8%9A%E0%B8%97%E0%B8%84%E0%B8%A7%E0%B8%B2%E0%B8%A1%E0%B8%97%E0%B8%B5%E0%B9%88%E0%B8%A1%E0%B8%B5%E0%B8%82%E0%B9%89%E0%B8%AD%E0%B8%84%E0%B8%A7%E0%B8%B2%E0%B8%A1%E0%B8%A0%E0%B8%B2%E0%B8%A9%E0%B8%B2%E0%B8%88%E0%B8%B5%E0%B8%99" title="หมวดหมู่:บทความที่มีข้อความภาษาจีน">บทความที่มีข้อความภาษาจีน</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"> หน้านี้แก้ไขล่าสุดเมื่อวันที่ 8 มกราคม 2561 เวลา 22:17 น.</li> <li id="footer-info-copyright"><div>อนุญาตให้เผยแพร่ภายใต้<a rel="nofollow" class="external text" href="//creativecommons.org/licenses/by-sa/4.0/">สัญญาอนุญาตครีเอทีฟคอมมอนส์ แบบแสดงที่มา-อนุญาตแบบเดียวกัน</a> และอาจมีเงื่อนไขเพิ่มเติม ดูรายละเอียดที่ <a class="external text" href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Terms_of_Use/th">ข้อกำหนดการใช้งาน</a><br /> Wikipedia® เป็นเครื่องหมายการค้าจดทะเบียนของ<a rel="nofollow" class="external text" href="https://www.wikimediafoundation.org">มูลนิธิวิกิมีเดีย</a> องค์กรไม่แสวงผลกำไร</div> <div class="noprint"><br /><a href="/wiki/%E0%B8%A7%E0%B8%B4%E0%B8%81%E0%B8%B4%E0%B8%9E%E0%B8%B5%E0%B9%80%E0%B8%94%E0%B8%B5%E0%B8%A2:%E0%B8%95%E0%B8%B4%E0%B8%94%E0%B8%95%E0%B9%88%E0%B8%AD" title="วิกิพีเดีย:ติดต่อ">ติดต่อเรา</a></div></li> </ul> <ul id="footer-places"> <li id="footer-places-privacy"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Privacy_policy">นโยบายความเป็นส่วนตัว</a></li> <li id="footer-places-about"><a href="/wiki/%E0%B8%A7%E0%B8%B4%E0%B8%81%E0%B8%B4%E0%B8%9E%E0%B8%B5%E0%B9%80%E0%B8%94%E0%B8%B5%E0%B8%A2:%E0%B9%80%E0%B8%81%E0%B8%B5%E0%B9%88%E0%B8%A2%E0%B8%A7%E0%B8%81%E0%B8%B1%E0%B8%9A">เกี่ยวกับวิกิพีเดีย</a></li> <li id="footer-places-disclaimers"><a href="/wiki/%E0%B8%A7%E0%B8%B4%E0%B8%81%E0%B8%B4%E0%B8%9E%E0%B8%B5%E0%B9%80%E0%B8%94%E0%B8%B5%E0%B8%A2:%E0%B8%82%E0%B9%89%E0%B8%AD%E0%B8%9B%E0%B8%8F%E0%B8%B4%E0%B9%80%E0%B8%AA%E0%B8%98%E0%B8%84%E0%B8%A7%E0%B8%B2%E0%B8%A1%E0%B8%A3%E0%B8%B1%E0%B8%9A%E0%B8%9C%E0%B8%B4%E0%B8%94%E0%B8%8A%E0%B8%AD%E0%B8%9A">ข้อปฏิเสธความรับผิดชอบ</a></li> <li id="footer-places-wm-codeofconduct"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Universal_Code_of_Conduct">จรรยาบรรณ</a></li> <li id="footer-places-developers"><a href="https://developer.wikimedia.org">ผู้พัฒนา</a></li> <li id="footer-places-statslink"><a href="https://stats.wikimedia.org/#/th.wikipedia.org">สถิติ</a></li> <li id="footer-places-cookiestatement"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Cookie_statement">นโยบายการใช้คุกกี้</a></li> <li id="footer-places-mobileview"><a href="//th.m.wikipedia.org/w/index.php?title=21&mobileaction=toggle_view_mobile" class="noprint stopMobileRedirectToggle">มุมมองสำหรับอุปกรณ์เคลื่อนที่</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-5ccf8d5c58-qxsm9","wgBackendResponseTime":201,"wgPageParseReport":{"limitreport":{"cputime":"0.230","walltime":"0.287","ppvisitednodes":{"value":752,"limit":1000000},"postexpandincludesize":{"value":17680,"limit":2097152},"templateargumentsize":{"value":479,"limit":2097152},"expansiondepth":{"value":13,"limit":100},"expensivefunctioncount":{"value":2,"limit":500},"unstrip-depth":{"value":0,"limit":20},"unstrip-size":{"value":0,"limit":5000000},"entityaccesscount":{"value":0,"limit":400},"timingprofile":["100.00% 266.533 1 -total","100.00% 266.533 1 แม่แบบ:กล่องข้อมูล_ตัวเลข"," 99.08% 264.093 1 แม่แบบ:Infobox_number/box"," 97.59% 260.104 1 แม่แบบ:Infobox"," 64.30% 171.386 1 แม่แบบ:Lang"," 4.14% 11.044 10 แม่แบบ:แปลงฐาน"," 3.16% 8.418 3 แม่แบบ:Infobox_number/link"," 2.60% 6.935 1 แม่แบบ:Ordinal"," 2.32% 6.181 1 แม่แบบ:Title_without_disambig"," 1.92% 5.120 1 แม่แบบ:Infobox_number/range"]},"scribunto":{"limitreport-timeusage":{"value":"0.169","limit":"10.000"},"limitreport-memusage":{"value":15664085,"limit":52428800}},"cachereport":{"origin":"mw-api-int.codfw.main-75f486866c-z7j7m","timestamp":"20241203120449","ttl":2592000,"transientcontent":false}}});});</script> <script type="application/ld+json">{"@context":"https:\/\/schema.org","@type":"Article","name":"21","url":"https:\/\/th.wikipedia.org\/wiki\/21","sameAs":"http:\/\/www.wikidata.org\/entity\/Q712477","mainEntity":"http:\/\/www.wikidata.org\/entity\/Q712477","author":{"@type":"Organization","name":"\u0e1c\u0e39\u0e49\u0e21\u0e35\u0e2a\u0e48\u0e27\u0e19\u0e23\u0e48\u0e27\u0e21\u0e01\u0e31\u0e1a\u0e42\u0e04\u0e23\u0e07\u0e01\u0e32\u0e23\u0e27\u0e34\u0e01\u0e34\u0e21\u0e35\u0e40\u0e14\u0e35\u0e22"},"publisher":{"@type":"Organization","name":"Wikimedia Foundation, Inc.","logo":{"@type":"ImageObject","url":"https:\/\/www.wikimedia.org\/static\/images\/wmf-hor-googpub.png"}},"datePublished":"2006-05-16T10:49:23Z","dateModified":"2018-01-08T15:17:02Z","headline":"\u0e15\u0e31\u0e27\u0e40\u0e25\u0e02\u0e18\u0e23\u0e23\u0e21\u0e0a\u0e32\u0e15\u0e34"}</script> </body> </html>