There are 10 questions in the math contest.
Analysis: * * * 10, so if you are all right, it should be 10× 10= 100, but if you are wrong, you won't get10, but you have to deduct 2 points, so every time you are wrong. In fact, he only got 64 points in the exam, so he lost 36 points. It can be concluded that * * * is wrong in three ways, and finally 10-3 is used to get the right seven ways.