Everyone knows that arithmetic is true: 2 + 2 = 4. But surprisingly, we don’t know why it’s true. By stepping outside the box of our usual way of thinking about numbers, my colleagues and I have ...

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 ...

A key part—though surely not the only part—of early-grades math is ensuring students get the basic arithmetic functions down and, beyond that, making sure they’re able to swiftly and automatically ...

The old way to multiply required a student to add the products of 36 x 4 and 36 x 2. The trick is to add that 0 at the end of the second product. Your fifth-grader asks you for help with the day's ...

When I was a kid learning arithmetic the only visual aid I remember is flash cards. These were useful for memorizing single-digit addition and multiplication, but is memorization really the best ...

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 ...

At the beginning of the 20th century, the German mathematician David Hilbert (1862–1943) advocated an ambitious program to formulate a system of axioms and rules of inference that would encompass all ...