Challenge yourself with number puzzles 200 mathematical logic puzzles to test your mental dexterity with this collection from The Times, like a mathematical crossword. Ideal for all fans of Su Doku who relish grappling with figures. Contains four levels of difficulty, combining arithmetic with an intersecting layout: Mild, Medium, Tricky and Tough. Kakuro originated in the United States in the 1950s under the name of Cross Sums. A logic puzzle, the aim is to complete a grid using digits from 1 to 9, with the digits in each row/column adding up to the clue for that block. It's similar to Su Doku in the sense that digits cannot be repeated in a row/column. Also known as: Croco Puzzle, Cross Sums, CrossSam, Kasan Kurosu, Kreuzsummenratsel,Tashizan Cross, Zahlenschwede Are you up to the challenge?