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