28. A number has 4 and 5 as factors. What other numbers must be factors? Why? What is the smallest number

this number could be?

2, 10.

Smallest number = 20.

Step-by-step explanation:

It must have 2 as a factor because 4 is a factor, and 2 is a factor of 4.

Also 4 * 5 = 20 so 10 must be a factor.

The smallest number possible is 20.