You first have to think of what to do.
First, you know that difference means sunbtraction.
You have to subtract 126 1/4 by 78 2/3.
You have to make the different denominators into the same denominator by multiplying the two denominators.
4 x 3= 12
If you did it to the bottom, do it to the top.
1/4 = ?/12
4 x 3 = 12
1 x 3= 3
1/4= 3/12
2/3= ?/12
3 x 4= 12
2 x 4= 8
2/3= 8/12
Subtract:
126 3/12 Regroup by taking a whole from 126 and make it into a fraction and add it to the other fraction.
-78 8/12 Ex:
________ 1 2/4 - 3/4
1= 4/4
4/4+2/4= 6/4
6/4-3/4= 3/4
Do the same for this problem, and at the end you should get 47 7/12.