The user goes first and selects one of the four number options. It is compulsary to choose a number during each turn for each player. The game will end at number 21.
After the user move, the computer chooses one number from the next set of four numbers. This cycle continues with the 'Total' counter being updated after each move.
As the counter moves closer to 21, the user must play in such a way that he/she can avoid choosing number 21 and play smartly to make the computer compulsarily choose 21. The player which has to choose 21, LOSSES the game.