4 + 3 = 7
7 + 3 = 10
6 + 3 = 9
5 + 3 = 8
10 + 3 = 13
 
12 − 2 = 10
8 − 2 = 6
9 − 2 = 7
7 − 2 = 5
10 − 2 = 8