Mensa''s Most Difficult Maths Tests provides an exceptional challenge for even the most adept of puzzlers. This full-colour book features a huge variety of numerical brainteasers that will test even the most mathematical of minds. With puzzles ranging from the familiar ¿ such as kakuro and killer sudoku - to the exotic ¿ such as sum skyscraper and calcudoku ¿ this fiendish puzzle book will keep you entertained for hours. Are you up to the challenge?