Emily Long is a freelance writer based in Salt Lake City. After graduating from Duke University, she spent several years reporting on the federal workforce for Government Executive, a publication of ...

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.

What’s seven times nine? Quick, you’ve got six seconds to answer. This June, over 600,000 children in England in year four, aged eight and nine, will be expected to answer questions like this. They ...