Mental Gymnastics Recreational Mathematics Puzzles Author:Dick Hess This original compilation features new mathematical puzzles as well as clever adaptations of traditional brainteasers. Suitable for ages 12 and older, it includes more than 120 challenges involving numbers, geometry, logic, and probability, plus story puzzles and playful game-related puzzles. Puzzles vary in difficulty; most require a bit of per... more »severance. Includes solutions.« less