How do you find the LCM of two fractions?

Answer 1

LCM means lowest common multiple. You cannot find the LCM of a fraction, but can find the LCM of two or more fractions. You do this by splitting the numbers up into their prime factors, then identifying any common factors. You then discard the duplicates of the common factors, and multiply all the others together. The answer is the LCM of the original numbers.

Answer 2

When it's between fractions, we call it the least common denominator, or LCD.
Example: 1/30 and 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
1/30 = 7/210
1/42 = 5/210

Answer 3

The same way as with regular numbers, except we call it the least common denominator when we're dealing with fractions.
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 LCD
1/30 = 7/210
1/42 = 5/210
1/30 + 1/42 = 12/210 or 2/35

Answer 4

LCM is applied to two or more fraction denominators. For 'A fraction' the denominator is the LCM.

Answer 5

The LCM is essentially the same thing as the lowest common denominator. To find the LCD, find the LCM of the denominators.

Answer 6

Factor them.

Example: 30 and 42

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