Sudoku

This game is an excellent choice for those who love how to train your brain. The goal of this game is to fill empty fields with numbers from 1 to 9 so to these figures is not repeated in the same row, column and 3x3 square. You will be given a 9x9 grid, which is divided into 9 identical squares. Some cells already contain numbers, and the rest are empty. The app is free.