You need to guess 4 digits in the right sequence in 9 tries or less. There are 3 levels of difficulties: Easy, Medium, and Hard in both duplicates and non-duplicates modes.

You can click a digit to add it to the attempt panel; swap digits in current attempt by drag 'n' drop, or simply drag away to remove a digit from current attempt.

If you suspect that a digit is in or out you can then tag it by tap and hold, or reset it to its initial state.

After choosing 4 different digits, you can click the Check button to get the result of your attempt.

Feedback Hints:
---- = None = all chosen digits don't exist
E = Exist = digit exists but is in wrong position
M = Match = digit exists and is in right position

The goal is to get to MMMM in the least number of attempts. The earlier you solve it, the more points you get. If however you fail to find the correct sequence, then the phone wins 9 points.