The first fraction has a denominator of 1 and the second fraction has
a denominator of 4. What is the smallest number that is divisible
by both 1 and 4. If you said 4, you are correct?

The first fraction has a denominator of 4, the second has a denominator
of 5, and the third has a denominator of 10. What is the smallest
number that is divisible by 4, 5, and 10? If you said 20, you are
correct?