15-7=
16-7=
13-8=
5+7-6=
11-9=
13-5=
11-5=
13-8+7=
12-8=
14-6=
14-7=
14-5-3=
( )
这个班有多少人?
90-2075-5 74-3100-20 30+4084-1
48-38+21 35+490-60 46+380-50
80-4042+7 6+5257-6 94-260+30