how to use hundreds chart for % of the numbers are multiples of 2 and 5?

Answer 1

5 out of 10 columns are multiples of 2, so 50% of all numbers are multiples of 2

2 out of 10 columns are multiples of 5, so 20% of all numbers are multiples of 5.

The % of the numbers that are multiples of both 2 and 5 us 50% * 20% = 10%