Jill,
Try converting 6 1/8 and 1 7/8 to fractions. It will be easier to ad and subtract a fraction. For instance 4 1/4 converted to a fraction would be 17/4.
6 1/8 - x = 1 7/8 ?
would it be 4 1/8 = x
3 answers
4 2\8
6 1/8=49/8
1 7/8=15/8
1 7/8=15/8