Sudoku.Summer

Sudoku is a fun number puzzle game that doesn't require any calculations or special math skills. All you need is a little concentration and logic.

The goal of Sudoku is to fill the free cells with numbers from 1 to 9 so that in each row, in each column and in each small 3 × 3 square, each number occurs only once. At the beginning of the game, some cells of the 9×9 grid will be filled. Your task is to fill in the missing numbers and fill in the entire grid using logic.