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