Today is Cinco de Mayo. And this year, the fifth of May is filled with mathematical joy. It is — Square Root Day! It all started in 1981. "I was writing a check in late August," says Ron Gordon, who ...

Square root days happen only a few times in a century, and the man who brought the day fame is celebrating his sixth one. Be square and get to the root of it! Celebrate Square Root Day today! Today is ...