Common core math

Question

what is 5 and 3 least common denominator

Answer 1

The least common multiple, LCM, is 15.

Answer 2

A denominator is the bottom number of a fraction. If you have (for example) 1/5 and 1/3, to find the least common denominator of the two fractions, you write out the multiples of the two denominators until you find the smallest number they have in common.

The first five multiples of 3 are: 3, 6, 9, 12, 15

The first five multiples of 5 are: 5, 10, 15, 20, 25

As you can see, the smallest number they have in common is 15. If you were to convert the fractions so that they both have 15 as their denominator, you multiply each numerator by whatever number you multiplied the denominator by to get 15. In this case, 3 x 5 = 15, and 5 x 3 = 15. Therefore, going back to my original example, 1/5 = 1 x 3 / 5 x 3 = 3/15, and 1/3 = 1 x 3 / 3 x 3 = 3/9.