Mensa's Most Difficult Number Puzzles

Prove your logical and arithmetical prowess by solving the exceptionally tricky problems in Mensa's Most Difficult Number Puzzles. This full-colour book features a huge variety of numerical conundrums that are certain to test even the most adept of puzzlers. Some puzzles - such as sum skyscraper and calcudoku - will test your mental maths, while others - such as touchy and bridges - will provide a trial for your logical and lateral thinking. Are you up to the fiendish challenge?