A primary school held a math contest with 15 questions. Every time he does a problem correctly, he gets 8 points. Every time he does a wrong question, he gets 4 points. Xiaoming got 72 points in the exam. How many questions did he get right? That's right. 1 1.

The analysis process is as follows:

Suppose he made a mistake in problem X.

According to the math contest held in a primary school, *** 15 questions, of which 15-x should be correct.

He got 8 points for each correct question, 4 points for each wrong question, and 72 points for Xiao Ming. Available quantity: 8( 15-x)-4x=72.

The solution is x=4.

Then we can get 15-4= 1 1. That's right. 1 1.

Extended data:

Law of integer division

(1) Start with the high order of the dividend, first look at how many digits there are in the dividend, and then try to divide the dividend by the first few digits. If it is smaller than the divisor, divide it by one digit as much as possible;

(2) Write the quotient on ex-dividend;

(3) The remainder after each division operation must be less than the divisor.

Solutions to such problems:

(1) Carefully examine the question, find out the meaning of the question, find out the unknown quantity, and set it as the unknown quantity.

(2) Find out the equivalence relation in the problem and list the equations.

(3) Solve the equation correctly.

(4) inspection.