15-9+8, 17-9+5, 18-(12-4), 12-(3+9), 18-9+5, 15-7+8

Question

15-9+8, 17-9+5, 18-(12-4), 12-(3+9), 18-9+5, 15-7+8

Answer 1

14,
13,
10,
0,
14,
16
......

Answer 2

15-9+8=14
17-9+5=13
18-(12-4)=10
12-(3+9)=0
18-9+5=14
15-7+8=16