Welk getal uit de tafel van 20 ontbreekt?
Tafels
1.
×
=
20
1
________
2.
×
=
20
3
________
3.
×
=
20
9
________
4.
×
=
20
10
________
5.
×
=
20
1
________
6.
×
=
20
5
________
7.
×
=
20
8
________
8.
×
=
20
5
________
9.
×
=
20
1
________
10.
×
=
20
8
________
11.
×
=
20
1
________
12.
×
=
20
9
________
13.
×
=
20
2
________
14.
×
=
20
6
________
15.
×
=
20
5
________
16.
×
=
20
9
________
17.
×
=
20
10
________
18.
×
=
20
3
________
19.
×
=
20
6
________
20.
×
=
20
2
________
21.
×
=
20
4
________
22.
×
=
20
2
________
23.
×
=
20
6
________
24.
×
=
20
7
________