The 2,300-year-old matrix is the world's oldest decimal multiplication table. From a few fragments out of a collection of 23-century-old bamboo strips, historians have pieced together what they say is ...

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.

From a few fragments out of a collection of 23-century-old bamboo strips, historians have pieced together what they say is the world's oldest example of a multiplication table in base 10. Five years ...