A Sudoku is a puzzle involving a 9x9 grid into which the numbers one to nine must be placed. The catch is that each row, column and 3x3 box has to contain each of the numbers one to nine once ...

Here's how you get to that astronomical sum. A Sudoku puzzle consists of a 9x9 grid of squares, broken up into a 3x3 grid of blocks made up of nine squares each. The goal of a puzzle is to fit the ...