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 ...

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 f… ...

But why do so many people struggle with fractions? In a recent article, psychologists Robert Siegler and Hugues Lortie-Forgues outline the reasons why rational number arithmetic is so difficult ...

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 ...

They identified a number of reasons why rational number arithmetic is so difficult, but these reasons can be divided into two classes— inherent and cultural sources of difficulty.