How do you figure the LCM of 12 and 30?

Answer 1

To find the LCM you first need to break the numbers down into their prime factors:

32 = 2x2x2x2x2

12 = 2x2x3

Next, you identify any common factors, and cross off the duplicates. In this case both numbers have two 2s as prime factors. That leaves us with 2, 2, 2, 2, 2 and 3. Multiplying these together gives 96.

Therefore the LCM of 32 and 12 is 96.

Answer 2

List the multiples.

12, 24, 36, 48, 60, 72

15, 30, 45, 60, 75

The LCM is 60

Factor them.

2 x 2 x 3 = 12

3 x 5 = 15

Combine the factors, eliminating duplicates.

2 x 2 x 3 x 5 = 60, the LCM

Answer 3

Factor them.

2 x 2 x 3 = 12

2 x 3 x 5 = 30

Combine the factors, eliminating duplicates.

2 x 2 x 3 x 5 = 60, the LCM

Answer 4

Factor them.

3

2 x 5

2 x 2 x 3

Combine the factors, eliminating duplicates.

2 x 2 x 3 x 5 = 60, the LCM.

Answer 5

The Least Common Multiple (LCM) for 12 30 14 is 420.

Answer 6

By making a table of their multiples and finding the first instance where the multiples match.

Answer 7

2 x 3 x 5 = 30

2 x 3 x 7 = 42

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