□+□=□ □-□=□
2+8=
12-6=
14-5=
18-3=
6+13=
12+7=
16-7=
11-8=
12-9=
13-6=
12-7=
14-9=
9+4=
12-10=
5+8=
(个)
8+=13
13-8=
8+=15
15-8=
+8=16
16-8=
8+=12
12−8=
(只)
问题: