7-1=6
6-1=5
9-8=1
3-9=-6
1-8=-7
7-8=-1
3-9=-6
6-1=5
7-1=6
8-8=0
2-9=-7
7-0=7
1-7=-6
12-6=6
2-8=-6
2-5=-3
12-3=9
14-7=7
12-1=11