Sudoku Gratis is a free digital version of the popular number puzzle game. The game is quite popular for several reasons. First, it takes only a few minutes to solve one of the puzzles at the easy or moderate level. Second, it takes quite a bit of logical thinking to solve these puzzles, so they stimulate cognitive maintenance and development. Lastly, the puzzles are casual enough that they create a sense of addictive gameplay.

Like other logic puzzles, sudoku is popular since it gives the player everything they need to win as long as the player has the skill. Knowing this makes it satisfying when you solve a puzzle, but frustrating when you can't. To solve a sudoku puzzle, you must completely fill out the 9x9 grid. Each of the smaller 3x3 grids that make up the larger 9x9 grid, and each row and column, must only contain one of each digit from 1 through 9.

The game will start off by giving you some of the numbers in the puzzle, and you solve it by using logic to determine where the other numbers can, can not, and must be. This app is one of the most straightforward and intuitive versions of the puzzle game on the market.