This is a classic puzzle game. Playing this game can improve your memory and problem-solving ability. In this game, you have three game modes to choose from: simple, medium and difficult. Now, use your brain to solve these problems!

Try to fill a 9×9 grid with digits so that each column, each row, and each of the nine 3×3 subgrids that compose the grid contain all of the digits from 1 to 9.