3 + 8 = 11
12 + 5 = 17
16 − 7 = 9
14 − 4 = 10
13 − 6 = 7
2 + 15 = 17
 

19 − 6 = 13
15 − 5 = 10
18 − 14 = 4
11 + 7 = 18
16 − 9 = 7
17 − 12 = 5