Math Olympiad

The application consists of 12 levels, the contestant starts from the first level and ends at level 12, according to the following rules:
1) Each level consists of several questions and each contestant's questions are different.
2) One point will add to the score of the contestant in the case of answered correctly and lose two points if he mistake in the answer.
3) When the balance of the contestant exceeds 15 points, he automatically moves to the top level.
4) If the contestant presses the start button, the timer starts, which records the number of minutes the user took to finish the level.
5) Contestants are ranked according to the number of minutes it takes per level on the attached statistics page within the app.
6) At levels 11 and 12 there are different rules of the game that you will find when you get there, good luck.