How do you get the least common denominator?

Answer 1

It's the same as the LCM only with denominators.

Example: 1/30 and 1/42

Factor them.

2 x 3 x 5 = 30

2 x 3 x 7 = 42

Select the highest amount of each factor.

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