Sudoku Paid

Traditional Sudoku game with 4 difficulty levels.
In Order to start a game press on a difficulty level. To abandon the current game and then start a new game press on the new game button.
To pause press the back button on your phone.
To show the solution to the sudoku press on show solution. Note that showing solution will end the game and you will need to start a new game.
Once you are done with solving the sudoku press the Check button to chek your answer.
Note that an empty box is represented by '+' sign.
To change the value of a box click on the box and then press on the number that you would like put in. Note that only boxes with gray letters are changeable.