Editing Mathematical coincidence (section)

== Introduction ==
A mathematical coincidence often involves an [[integer]], and the surprising feature is the fact that a [[real number]] arising in some context is considered by some standard as a "close" approximation to a small integer or to a multiple or power of ten, or more generally, to a [[rational number]] with a small [[denominator]].  Other kinds of mathematical coincidences, such as integers simultaneously satisfying multiple seemingly unrelated criteria or coincidences regarding units of measurement, may also be considered.  In the class of those coincidences that are of a purely mathematical sort, some simply result from sometimes very deep mathematical facts, while others appear to come 'out of the blue'.

Given the [[countably infinite]] number of ways of forming mathematical expressions using a finite number of symbols, the number of symbols used and the [[Arithmetic precision|precision]] of approximate equality might be the most obvious way to assess mathematical coincidences; but there is no standard, and the [[strong law of small numbers]] is the sort of thing one has to appeal to with no formal opposing mathematical guidance.{{Citation needed|date=May 2009}} Beyond this, some sense of [[Mathematical beauty|mathematical aesthetics]] could be invoked to adjudicate the value of a mathematical coincidence, and there are in fact exceptional cases of true mathematical significance (see [[Ramanujan's constant]] below, which made it into print some years ago as a scientific [[April Fools' Day|April Fools']] joke<ref name="gardner">Reprinted as {{Cite book|last1=Gardner|first1=Martin|authorlink1=Martin Gardner|title=The Colossal Book of Mathematics|url=https://archive.org/details/colossalbookmath00gard|url-access=limited|year=2001|publisher=W. W. Norton & Company|location=New York|isbn=978-0-393-02023-6|pages=[https://archive.org/details/colossalbookmath00gard/page/n690 674]–694|chapter=Six Sensational Discoveries}}</ref>).  All in all, though, they are generally to be considered for their curiosity value, or perhaps to encourage new mathematical learners at an elementary level.