A sudoku game (RULES bellow) - choose the difficulty (hard might take a minute) - select a square by clicking it - change its value with by typing a number - 0 to erase (/ X in mobile mode) - "check" to see if you have won / have a correct non-complete grid) SUDOKU Game : The goal of the SUDOKU is to fill all lines / columns / "big square of 3x3"; (that's 9 "little squares" each time) with ALL the digits form 1 to 9 included. You can do that by completion (if there are all digits but one on a line, column, or 3x3square, that means that it's this one that is in the last gap) elimination (there isn't a 1 as an example in this 3x3square yet that mean you "need a 1 in it", you then look for other 1 an d where you find them, there isn't any more 1 on the same line or column, this way can possibly find the ONLY remaining square it can be on the square of 3x3. It works the same for lines, columns and with any digit)