Mathemagic: 169 Astonishing Numerical Challenges by Raymond Blum
This enormous volume of maths puzzles will test how sharp readers are with numbers and provide hours of fun. There are mind bogglers of every type - from amazing 'magic' number tricks to beautiful geometric designs - and plenty of them too! This starts with puzzles that are fairly easy and builds up to ones that are really challenging. Tricks and hints provide help along the way that will make the reader look like a whiz!