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src="/web/20100520023206im_/http://mathworld.wolfram.com/images/entries/underline.gif" width="100%" height="3" alt=""/><img src="/web/20100520023206im_/http://mathworld.wolfram.com/images/entries/underline.gif" width="20" height="3" alt=""/></span></td><td><img src="/web/20100520023206im_/http://mathworld.wolfram.com/images/spacer.gif" height="15" alt=""/></td></tr> </table>  </td> </tr> <tr valign="top"> <td>  <a href="https://web.archive.org/web/20100520023206/http://mathworld.wolfram.com/notebooks/Arithmetic/Duodecimal.nb" onclick="downloadNotebook('https://web.archive.org/web/20100520023206/http://mathworld.wolfram.com/notebooks/Arithmetic/Duodecimal.nb');return false;"><img src="/web/20100520023206im_/http://mathworld.wolfram.com/images/entries/dnld-nb.gif" width="119" height="26" border="0" alt="DOWNLOAD Mathematica Notebook"/></a> <span><a href="/web/20100520023206/http://mathworld.wolfram.com/contribute/incomplete_entry.html#Duodecimal"><img src="/web/20100520023206im_/http://mathworld.wolfram.com/images/entries/contribute2.gif" align="bottom" border="0" width="91" height="26" alt="Contribute to this entry"/></a></span>  <p class="Text"> The base-12 number system composed of the digits 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B. Such a system has been advocated by no less than Herbert Spencer, John Quincy Adams, and George Bernard Shaw (Gardner 1984). In fact, duodecimal still has its advocates, some of whom term it "dozenal." </p> <p class="Text"> Some aspects of a base-12 system are preserved in the terms <a href="/web/20100520023206/http://mathworld.wolfram.com/Dozen.html" class="Hyperlink">dozen</a> and <a href="/web/20100520023206/http://mathworld.wolfram.com/Gross.html" class="Hyperlink">gross</a> applied to the quantities 12 and 144, respectively. </p> <p class="Text"> The following table gives the duodecimal equivalents of the first few decimal numbers. </p> <table align="center" class="mathworldtable"> <tr style="Text"><td align="right">1</td><td align="right">1</td><td align="left">11</td><td align="right">B</td><td align="right">21</td><td align="left">19</td></tr><tr style="Text"><td align="right">2</td><td align="right">2</td><td align="left">12</td><td align="right">10</td><td align="right">22</td><td align="left">1A</td></tr><tr style="Text"><td align="right">3</td><td align="right">3</td><td align="left">13</td><td align="right">11</td><td align="right">23</td><td align="left">1B</td></tr><tr style="Text"><td align="right">4</td><td align="right">4</td><td align="left">14</td><td align="right">12</td><td align="right">24</td><td align="left">20</td></tr><tr style="Text"><td align="right">5</td><td align="right">5</td><td align="left">15</td><td align="right">13</td><td align="right">25</td><td align="left">21</td></tr><tr style="Text"><td align="right">6</td><td align="right">6</td><td align="left">16</td><td align="right">14</td><td align="right">26</td><td align="left">22</td></tr><tr style="Text"><td align="right">7</td><td align="right">7</td><td align="left">17</td><td align="right">15</td><td align="right">27</td><td align="left">23</td></tr><tr style="Text"><td align="right">8</td><td align="right">8</td><td align="left">18</td><td align="right">16</td><td align="right">28</td><td align="left">24</td></tr><tr style="Text"><td align="right">9</td><td align="right">9</td><td align="left">19</td><td align="right">17</td><td align="right">29</td><td align="left">25</td></tr><tr style="Text"><td align="right">10</td><td align="right">A</td><td align="left">20</td><td align="right">18</td><td align="right">30</td><td align="left">26</td></tr> </table>   <form name="SearchLinks" method="get" action="https://web.archive.org/web/20100520023206/http://mathworld.wolfram.com/search/"> <p class="CrossRefs"> <span class="crosslinkheader">SEE ALSO:</span> <a href="/web/20100520023206/http://mathworld.wolfram.com/12.html" class="Hyperlink">12</a>, <a href="/web/20100520023206/http://mathworld.wolfram.com/Base.html" class="Hyperlink">Base</a>, <a href="/web/20100520023206/http://mathworld.wolfram.com/Decimal.html" class="Hyperlink">Decimal</a>, <a href="/web/20100520023206/http://mathworld.wolfram.com/Dozen.html" class="Hyperlink">Dozen</a>, <a href="/web/20100520023206/http://mathworld.wolfram.com/Gross.html" class="Hyperlink">Gross</a>, <a href="/web/20100520023206/http://mathworld.wolfram.com/Hexadecimal.html" class="Hyperlink">Hexadecimal</a> </p> </form>       <p> <img src="/web/20100520023206im_/http://mathworld.wolfram.com/images/entries/underline.gif" width="300" height="3" alt=""/> </p> <span class="crosslinkheader">REFERENCES:</span> <p class="Reference"> Andrews, F. E. "An Excursion in Numbers." <i>Atlantic Monthly.</i> Oct. 1934. </p> <p class="Reference"> Andrews, F. E. "My Love Affair with Dozens." <i>Michigan Quart. Rev.</i> <b>11</b>, Spring 1972. <a href="https://web.archive.org/web/20100520023206/http://www.dozenal.org/files/E3a%20My%20love%20affair.pdf" class="Hyperlink">http://www.dozenal.org/files/E3a%20My%20love%20affair.pdf</a>. </p> <p class="Reference"> Dozenal Society of America. <a href="https://web.archive.org/web/20100520023206/http://www.dozenal.org/" class="Hyperlink">http://www.dozenal.org/</a>. </p> <p class="Reference"> Gardner, M. <i><a href="https://web.archive.org/web/20100520023206/http://www.amazon.com/exec/obidos/ASIN/0226282503/ref=nosim/weisstein-20" class="Hyperlink">The Sixth Book of Mathematical Games from Scientific American.</a></i> Chicago, IL: University of Chicago Press, pp. 104-105, 1984. </p>   <div> <img src="/web/20100520023206im_/http://mathworld.wolfram.com/images/entries/underline.gif" width="300" height="3" alt=""/><br/><br/><br/><span class="crosslinkheader">CITE THIS AS:</span><br/> <p class="citation"> <a href="/web/20100520023206/http://mathworld.wolfram.com/about/author.html">Weisstein, Eric W.</a> "Duodecimal." 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