This requires an algorithm: students are taught to stack one number atop another and multiply each digit of the bottom number ...

Mathematicians love a good puzzle. Even something as abstract as multiplying matrices (two-dimensional tables of numbers) can feel like a game when you try to find the most efficient way to do it.

Most people know just one way to multiply two large numbers by hand. Typically, they learned it in elementary school. They’re often surprised to find that there are a variety of ways to do ...