You start the game by clicking the play button. Two (2) numbers are generated when the play button is clicked. If the sum of the two numbers is equal to 21, you win, if the sum of the two numbers is less than 21, you click on the hit button to add another number to the sum. You win if the new sum is equal to 21 and you lose if the new sum is greater than 21. You can add another number to the sum if it is still less than 21.