Most of us have little trouble working out how many millilitres are in 2.4 litres of water (it’s 2,400). But the same can’t ...

For years, a French mathematician searched for a proof that a gigantic number is prime. His method is still used 150 years ...

When counting squares in a grid, don’t stop at the smallest boxes; the bigger ones are hiding too. The rule is simple: In an n × n grid—where n is the number of squares both horizontally and ...