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