{"id":226,"date":"2019-06-26T23:05:40","date_gmt":"2019-06-26T23:05:40","guid":{"rendered":"http:\/\/funfacts.104.42.120.246.xip.io\/?page_id=226"},"modified":"2019-12-03T22:16:55","modified_gmt":"2019-12-03T22:16:55","slug":"making-history-by-card-shuffling","status":"publish","type":"page","link":"https:\/\/math.hmc.edu\/funfacts\/making-history-by-card-shuffling\/","title":{"rendered":"Making History by Card Shuffling"},"content":{"rendered":"\n<p>Did you know that whenever you shuffle a deck of cards, it is quite likely that you are making history?<\/p>\n\n\n\n<p>A deck of 52 cards can be ordered in 52! = 52 x 51 x 50 x&#8230;x 2 x 1 ways. This is because there are 52 ways to choose the first card, 51 ways to choose the 2nd, 50 ways to choose the 3rd, etc. But 52! is a very large number: larger than<\/p>\n\n\n\n<p>8 x 10<sup>67<\/sup>.<\/p>\n\n\n\n<p>How big is this number? Well, someone shuffling a deck of cards once per second since the beginning of the universe (believed to be about 14 billion years ago) would not have shuffled the deck more than 10<sup>18<\/sup>times.<\/p>\n\n\n\n<p>Thus it is quite likely that any given configuration achieved through&nbsp;random&nbsp;shuffling has never appeared before in the history of shuffling!<\/p>\n\n\n\n<p><strong>Presentation&nbsp;Suggestions:<\/strong><br>You might also compare 10<sup>67<\/sup>&nbsp;to other large numbers or the number of stars in the universe (10<sup>23<\/sup>).<\/p>\n\n\n\n<p><strong>The&nbsp;Math&nbsp;Behind&nbsp;the&nbsp;Fact:<\/strong><br>We ought to be a little careful here. In reality, there are many kinds of shuffles and not all of them involve randomness, e.g., see the Fun Fact&nbsp;Perfect Shuffles. In order for the result of a shuffle to produce an independent configuration, we must use a shuffle with inherent randomness.<\/p>\n\n\n\n<p>But even a single random riffle shuffle does not make every configuration equally likely, so a single random riffle shuffle will not produce an independent ordering of cards. However a single random riffle shuffle produces nearly 2<sup>52<\/sup>&nbsp;possible configurations, which is still a very large number (4.5&#215;10<sup>15<\/sup>), and after seven random riffle shuffles nearly every configuration is equally likely to occur, as explained in the Fun Fact&nbsp;Seven Shuffles. So it is still very likely that each random riffle shuffle is truly &#8220;making history&#8221;.<\/p>\n\n\n\n<p><strong>How to Cite this Page:<\/strong>&nbsp;<br>Su, Francis E., et al. &#8220;Making History by Card Shuffling.&#8221;&nbsp;<em>Math Fun Facts<\/em>. &lt;http:\/\/www.math.hmc.edu\/funfacts&gt;.<\/p>\n\n\n\n<p><strong>Fun Fact suggested by:   <\/strong><br>Lew Ludwig <\/p>\n","protected":false},"excerpt":{"rendered":"<p>Did you know that whenever you shuffle a deck of cards, it is quite likely that you are making history?&#46;&#46;&#46;<\/p>\n","protected":false},"author":7,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"tags":[9,3,12,45,165],"class_list":["post-226","page","type-page","status-publish","hentry","tag-combinatorics","tag-easy","tag-other","tag-probability","tag-universe"],"jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/math.hmc.edu\/funfacts\/wp-json\/wp\/v2\/pages\/226","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/math.hmc.edu\/funfacts\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/math.hmc.edu\/funfacts\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/math.hmc.edu\/funfacts\/wp-json\/wp\/v2\/users\/7"}],"replies":[{"embeddable":true,"href":"https:\/\/math.hmc.edu\/funfacts\/wp-json\/wp\/v2\/comments?post=226"}],"version-history":[{"count":4,"href":"https:\/\/math.hmc.edu\/funfacts\/wp-json\/wp\/v2\/pages\/226\/revisions"}],"predecessor-version":[{"id":1516,"href":"https:\/\/math.hmc.edu\/funfacts\/wp-json\/wp\/v2\/pages\/226\/revisions\/1516"}],"wp:attachment":[{"href":"https:\/\/math.hmc.edu\/funfacts\/wp-json\/wp\/v2\/media?parent=226"}],"wp:term":[{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/math.hmc.edu\/funfacts\/wp-json\/wp\/v2\/tags?post=226"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}