Question

A student gave the difference 27 - 8/7 as 19/7. Her teacher did not give her any credit for this answer. What went wrong?

Answer 1

She should have made the two numbers into like fractions. See below for more details.

Explanation:

What the student did:

`27-(8)/(7) =(19)/(7)`

What she should have actually done:

`27-(8)/(7) = (27*7)/(7) - (8)/(7) = (189)/(7) - (8)/(7) = (181)/(7)`

181/7 is the answer.