My child is working through basic operations, and gave this problem:

23 + 17 * 2 / 8 + 11 = 13

The teacher wants the parenthesis to be put in the right places to come up with 13. My father is a former math teacher, and he could solve, I asked a couple of financial engineer I work with and they could get it. Now I'm asking you, please help. Other wise I will have to kill the teacher.


Hi David,

The answer expected is probably

[23 + (17*2)]/(8+11) = (1)(3)

When I first looked at it I thought there must be a misprint. If 13 is a misprint and should be 3 then:

[23 + (17*2)]/(8+11) = 3

If with *2 being a misprint then:

2(3+1)7/(8+11) = 247/19 = 13

The point of these exercises is to show how important parentheses are. The students who do not realize this have lots of problem in high school algebra.

Go to Math Central