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 ...

Happy Square Root Day! Apparently, April 4, 2016 is one of the unofficial holidays that occur when the month and day are the square root of the last two digits of the year. (In this case, month number ...