MathEMagic 169 Astonishing Numerical Challenges Author:Raymond Blum, Adam Hart-Davis, Bob Lange, Derrick Niederman This enormous volume of math 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 ch... more »allenging. Tricks and hints provide help along the way that will make the reader look like a whiz!« less