Erbijsommen en erafsommen tot 20 oplossen
In de mix
1.
17
2
+
=
2.
12
0
+
=
3.
16
12
–
=
4.
13
12
–
=
5.
15
12
–
=
6.
15
1
+
=
7.
15
3
+
=
8.
12
1
+
=
9.
12
1
+
=
10.
14
12
–
=
11.
16
14
–
=
12.
12
1
+
=
13.
12
4
+
=
14.
18
13
–
=
15.
12
1
+
=
16.
14
13
–
=
17.
12
1
+
=
18.
13
1
+
=
19.
14
13
–
=
20.
17
1
+
=
21.
14
12
–
=
22.
13
12
–
=
23.
16
4
+
=
24.
16
14
–
=