According to the meaning of the question, if all 20 questions are answered correctly, you will get 100 points, if one question is answered incorrectly, you will get (5+3) points, and if you don't answer, you will get only 5 points. Xiao Li lost (100-79). Then, according to (100-79)÷8=2 (questions) ... 5 (points), analyze the number of correct, wrong and unanswered questions.

Solution: (5×20-75)÷8=2 (topic) ... 5 points.

20-2- 1= 17 (title)

The law of quotient changing with dividend and divisor;

1, dividend and divisor are multiplied or divided by a non-zero number at the same time, and the quotient remains unchanged.

2. The divisor is expanded (or reduced) several times, and the quotient is expanded (or reduced) several times under the condition that the divisor is unchanged.

3. The divisor is constant, and if the divisor is expanded (or reduced) several times, the quotient will be reduced (or expanded) several times.