This week would have been the 100th birthday of Martin Gardner, who is deservedly credited with turning on several generations of people worldwide to the pleasures of maths! To mark the occasion here are some favourite puzzles that, apart from being fun, also lead to some serious maths.

Making a very special number out of primes.

Try this interactive sudoku-esque puzzle, kindly provided by Muddled Puzzles!

Katastrophion is a level up from Logikion — if you like sudoku, you'll like this!