Solve the math problem.
8 - 8 =
8
- 7
8 - 2 =
20
- 2
9
15
- 1
17 - 2 =
19
- 0
17 - 4 =
7 - 5 =
16
- 5
18
17 - 6 =
14
- 9
12 - 5 =
6 - 6 =
11
- 6
18 - 9 =
13 - 7 =
4 - 2 =
12 - 3 =