Myths of maths: The four colour theorem
It's one of mathematics' most famous results: every "map" can be coloured using at most four colours. What it doesn't usually apply to, however, are real maps.
With just a few months to go until the UEFA European Cup, here's how you can make your office sweepstake a lot fairer and more exciting.
After 2000 years of searching we only know of 51 perfect numbers and they're all even. What else do and don't we know about these rare and precious jewels of maths?