Substraction Chart:

+ 0 1 2 3 4 5 6 7 8 9 10
0 0 -1 -2 -3 -4 -5 -6 -7 -8 -9 -10
1 1 0 -1 -2 -3 -4 -5 -6 -7 -8 -9
2 2 1 0 -1 -2 -3 -4 -5 -6 -7 -8
3 3 2 1 0 -1 -2 -3 -4 -5 -6 -7
4 4 3 2 1 0 -1 -2 -3 -4 -5 -6
5 5 4 3 2 1 0 -1 -2 -3 -4 -5
6 6 5 4 3 2 1 0 -1 -2 -3 -4
7 7 6 5 4 3 2 1 0 -1 -2 -3
8 8 7 6 5 4 3 2 1 0 -1 -2
9 9 8 7 6 5 4 3 2 1 0 -1
10 10 9 8 7 6 5 4 3 2 1 0

5 - 6 = -1

7 - 9 = -2

2 - 1 = 1

10 - 8 = 2

3 - 7 = -4

9 - 9 = 0

2 - 3 = -1

3 - 5 = -2