Game Fun Sudoku

If you want to spend some time entertaining, try to play this solitaire, surely you've heard of him, the Sudoku. You have a grid with 9 boxes, and these in turn, have 9 smaller boxes, in each box you have to place a number, but you must think very well before putting it. You can not repeat the same number in the same row, in the same column, or in the same 3x3 box. You should look twice before placing any number.