A mathematical coincidence can be said to occur when two expressions show a near-equality that lacks direct theoretical explanation. For example, there is a near-equality around the round number 1000 between powers of two and powers of ten: 
. Some of these coincidences are used in engineering when one expression is taken as an approximation of the other.
It's always the simple things that get me.
OK, maybe you don't find that equation as fascinating as I do.
But I also get distracted by shiny objects and Wheel of Fortune.