How do you find the least common denominatior of fractions?

Answer 1

It's the same process as finding the least common multiple.

Example: 7/30 + 13/42

Factor them.

2 x 3 x 5 = 30

2 x 3 x 7 = 42

Combine the factors, eliminating duplicates.

2 x 3 x 5 x 7 = 210, the LCM

Since 210 is the lowest common denominator, we can proceed to add them.

7/30 = 49/210

13/42 = 65/210

7/30 + 13/42 = 114/210 or 19/35 in lowest terms.