How do you find the LCM with a factor tree?

Answer 1

The factor tree finds the prime factorization. The prime factorization finds the LCM.

Example: 30 and 42

Factor them.

30

15,2

5,3,2

42

21,2

7,3,2

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