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 ...

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 ...

Using fundamental processes instead of brain cells, plants measure the time until dawn and divide that by their stored starch levels. Researchers say that this ability in plants represents the first ...