This classic puzzle is enjoyed by millions of people the world over.
How it works
Each 9×9 grid must be filled with the numbers 1-9 exactly once each. Similarly each row and column of 9 cells must also have the numbers 1-9 exactly once each. Given a particular starting point, only a single arrangement of numbers will solve the grid.
Each book in this range has hundreds of Sudoku puzzles with dozens of other fun puzzles and games also included.