How do you work out LCM?

Answer 1

To find the Least Common Multiple (LCM) of two or more numbers, write down the multiples of the numbers until they match. I will use 6 and 9 as an example.

6: 6, 12, 18...

9: 9, 18, 27...

The numbers in bold are your LCMs. 18 is the LCM of 6 and 9.

Answer 2

Example: 30 and 42

Factor them.

2 x 3 x 5 = 30

2 x 3 x 7 = 42

Select the common factors.

2 x 3 = 6, the GCF

Select the highest amount of each factor.

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

Check it.

30 x 42 = 1260

210 x 6 = 1260

It checks.

Answer 3

2