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