Old phone numbers in the U.S. had letters to denote the telephone exchange that handled any given number, a practice that lasted until the late 1970s.

The ancient Greeks were incredibly talented mathematicians—but they rarely used numbers in their math. Their particular specialty, geometry, dances around actual quantities, focusing on higher ...

Believe it or not, there was a time when phone numbers used to have letters in front of them. It may seem strange now, but there was a very good reason for it.