24 The Challenging New Number Puzzle (Paperback)  | Released: 2010

24 is a challenging new cross-number puzzle that combines problem-solving, logical thinking and elementary Mathematics. The puzzles involve the level of Maths taught at school, featuring brackets, powers, roots, decimals, factorials, negative numbers, estimating and so on. Solvers are advised to tackle them with the aid of a simple scientific calculator, although they may enjoy the challenge of attempting them without one. The puzzles take the form of a symmetrical grid and twenty-four clues. A selection of four digits is given at the top of each puzzle which the solver must combine in the correct way in order to obtain the number 24 each time. Each puzzle should take between 30 and 50 minutes to solve.