I have been looking at various arithmetic materials for lower elementary school students, and one that I recently felt was "quite easy to use" is Arithmetic Lab.I had owned it for a while, and at ...

Arithmetic for middle school entrance exams. Even when the answer is correct on cram school tests or homework, when you ask, ...

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 ...

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 ...

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 ...