What is the least common denominator of 5 and 15?

Answer 1

The least common denominator of any two integers is 1. To see this, convert the integers to fractions so they actually have denominators.

5 = 5/1

15 = 15/1

The denominators are both 1, so they are already common. 1 cannot be reduced, so they are already least. So, the LCD of 5 and 15 is 1.

You may have intended to ask about the least common multiple, which makes more sense for integers. For this, list the multiples of each number, and find the lowest number in both lists.

5 = 5, 10, 15, 20, 25

15 = 15, 30, 45, 60, 75

The lowest number in both lists is 15, and so 15 is the lowest common multiple (LCM) of 5 and 15.