37-6+20=
60-4-30=
25+5-9=
42+(12-3)=
58+(26-6)=
84-(32+8)=
36-(9-1) 64+20
39+8 22+(3+2)
37-10 52-(8-3)
14+(3+67) 32-4
28-7+ 5
30-6-8
20-(9-8)
22+(15-7)
14-9-3=8
79-8+1=70
。
8