I believe that it is the second and third boxes
This is not my work but i hope this can help you with your problem
https://answers.yahoo.com/question/index?qid=20120518194118AAhi738

Change the mixed fractions to improper fractions.
To do this, multiply the whole number part by the denominator. Add that to the numerator. Then write the result on top of the denominator.
You would now have:

Change the division sign to a multiplication sign by turning the second fraction upside down.
That is,

The answer is:

This can be simplified to: