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