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