“The Secret Lives of Numbers,” by Kate Kitagawa and Timothy Revell, highlights overlooked contributions to the field by ancient thinkers, non-Westerners and women. By Alec Wilkinson Alec Wilkinson is ...

Math is, by definition, a subject about numbers. But at the National Council of Teachers of Mathematics this week, math educators said the subject has its own language, too—and knowing how to speak it ...