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 ...

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 ...

In the early years of the Republic, arithmetic was generally taught to teenaged boys planning careers in commerce, often by private tutors. With the advent of free common or elementary schools ...

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 ...

On his website andertoons.com, illustrator Mark Anderson has a cartoon in which a boy is handing his teacher an assignment. “To show how well I understand fractions,” he says, “I only did half of my ...

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 ...