Numbers 0 through 9 each have a number of something.
0 has 6.
1 has 2.
2 has 5.
3 has 5.
4 has 4.
How many do 5, 6, 7, 8 and 9 have?
5 has:
5
6 has:
6
7 has:
3
8 has:
7
and 9 has:
6
The explanation is:
These are the number of segments lit up on a 7-segment LED/LCD display for the corresponding numbers.
Image courtesy Wikipedia's page on 7-segment displays