I saw a math problem in the second grade of primary school in the newspaper these two days. For the second grade of primary school, only the addition and subtraction operations within 100 digits are involved. The topic is simple, but now it is controversial. Why does such a simple math problem attract so many people's attention?

The topic is this: Xiao Li is 7 years old, her grandfather is 48 years older than Xiao Li, and her mother is 36 years younger than her grandfather. How old is her mother this year?

This kind of problem is actually to examine students' addition operation. Grandpa's age = Xiaoli's age +48, then 7+48=55, then Grandpa's age is 55, Mom's age = Grandpa's age -36, then 55-36= 19, then Mom's age is 19.

This is the student's answer. The calculation is correct and the logic is correct. Why was it corrected wrong? The students recalculated several times and got the same answer, so they cried and asked their parents what happened. Parents also have no solution, so they put the question on the post bar for help.

Some netizens said: "The students' answers lack description and explanation. "Some netizens think:" The students have done nothing wrong on this issue, but the teacher should have corrected it. " Others turned their attention to mother's age and questioned her age. Her mother 19 years old, Xiaoli is 7 years old. Are they creatures?

This kind of question is to calculate the age, but actually to compare the size of the number. As long as the relationship between the two numbers is clarified, the age of grandpa can be calculated from the age relationship between Xiaoli and grandpa, and then the age relationship between mom and grandpa can be calculated, and the answer can be obtained. Then, the student's answer is right, why is it wrong? What's wrong with this question?