In this book: Pages: 319 Puzzle Quantity: 1200 Puzzles Per Page: 6 Puzzles on each page Levels: 4 Levels - Easy to Very Hard Answers: Provided in smaller print size Sudoku is a logic-based, combinatorial number-placement puzzle. The objective is to fill a 9×9 grid with digits so that each column, each row, and each of the nine 3×3 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.