You’ll have a much easier time winning at Tic Tac Toe if you’re going first; however, the chances decrease depending on how your opponent responds to your first move. In a best case scenario: Assuming ...

Up to equivalence, there aren’t nine distinct opening moves. There are only three. If it isn’t immediately clear to you what “up to equivalence” means here, I urge you to try and figure it out ...

This piece was adapted from an article originally published in 1957 by the mathematician and master puzzler Martin Gardner. For 25 years, Gardner wrote a beloved column called “Mathematical Games” for ...