Complete the table so that each row, column and box (3-by-3 framed grid or block) contains the numbers 1 through 9 only once. Sudoku, just like Jigsaw, Crossword, and other puzzles, is a game of pure logic, and much like chess it requires some higher thinking, particularly for levels 4 and 5. Each answer to each puzzle is unique and no guessing or math should be involved.