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