Randolph Grace receives funding from the Marsden Fund, administered by the Royal Society of New Zealand. Everyone knows that arithmetic is true: 2 + 2 = 4. But surprisingly, we don’t know why it’s ...

Barbie caught a lot of flack back in the ’90s for declaring, “Math class is tough!” Today we find ourselves in the disorienting position of defending her. We recently got a note from an anonymous ...

Dr. JeFreda R. Brown is a financial consultant, Certified Financial Education Instructor, and researcher who has assisted thousands of clients over a more than two-decade career. She is the CEO of ...

Consider this sequence of numbers: 5, 7, 9. Can you spot the pattern? Here’s another with the same pattern: 15, 19, 23. One more: 232, 235, 238. “Three equally spaced things,” says Raghu Meka, a ...

You may never have heard of modular arithmetic, but you use it every day without the slightest difficulty. In this system, numbers wrap around when they reach a certain size called the modulus; it is ...