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