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 ...

Q: How much is 230 times 10? A: The number of years humans have been calculating with decimals. A crack team of scholars in Beijing learned this last year when they solved a 23-centuries-old puzzle.

Practise your 2 times tables with this quiz. The 5 times table Learn all about the 5 times table and find out about multiples of 5. The 10 times table Discover the 10 times tables and try this quiz.