1
+
____________________
=
3
5
+
____________________
=
15
____________________
+
8
=
15
____________________
+
3
=
12
3
+
4
=
____________________
21
-
3
=
____________________
5
-
____________________
=
0
6
-
____________________
=
2
____________________
-
4
=
6
____________________
-
8
=
6
5
-
4
=
1
