7+=15 27-=20 -4=30
17-=9 6+=15 13-6=-7
12-3=
14-7=
8+4=
30+7=
42-2=
50+6=
20-9=
55-50=
36-6=
63-3=
25-5=
77-70=
7+9-8=
64-60+8=
17-9-2=
15-79 45-550 57-505
4+813 7+6076 12-57
14-8=
16-9=
78-70=
6+8-9=
6+7=
6+70=
11-5=
16-8+7=
17-8-3=
5+4+7=
44-4+6=
12->5 8+<17 <64-60
= (个) = (个)