How do you find the least common denomonater?

Answer 1

It's the same as finding an LCM. Example: 1/30 + 1/42

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

1/30 = 7/210

1/42 = 5/210

The sum is 12/210 or 6/105