The game is very simple and tends to make fun out of practicing basic math calculations.
At the beginning the two random numbers appears on the board. Player and opponent choose two of them and make subtractions by turn. The one who is unable to make a move loses the game.
"Hint" button allows to find out the number of the next move by solving simple math equation or answering on question.
"You start" button gives a privilege of first move to the opponent. Do so, if you calculated or guessed that making a first move will result to the lost of the game.
"Reset" button simply reset current game.