Ok so I have a few equations here:
17 3/4 - 4 1/4 =
A. 13 2/8
B. 21 2/4
C. 13 2/4
D. 14
_____________
23 5/8 - 12 3/8 =
a. 12
b. 11
c. 11 2/16
d. 11 2/8
________________
6 11/12
- 3 9/12
a.2 2/12
b.3 2/12
c.3 2/24
d.9 20/12
_________
21 1/2 - 6 1/2 =
a.15
b.15 1/2
c.15 2/4
d.16