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