In this puzzle book, you will find 280 Sudoku puzzles at levels Easy, Medium, Hard, Very Hard and Evil. Puzzles: 280, Levels Easy - Evil. Pages: 162 pages, 2 puzzles per page. Answers: Provided, small print. Puzzle numbers are in large print and clearly visible with margins along the sides of each puzzle to allow space for calculations. Sudoku is a logic-based, combinatorial number-placement puzzle. The objective is to fill a 9x9 grid with digits so that each column, each row, and each of the nine 3x3 sub-grids that compose the grid contain all of the digits from 1 to 9. You do not have to be great at mathematics, but you will surely increase your memory and concentration powers. Through playing Sudoku you can greatly reduce the chances of developing Alzheimer's by keeping your brain active.