Question

explain how the LCM of 12 15 and 21 is 420​

Answer 1

12 = 2 × 2 × 3

15 = 3 × 5

21 = 3 × 7

HCF = 3

LCM = 3 × 2 × 2 × 5 × 7

LCM = 420

Answer 2

LCM = Least Common Factor

To find the LCM of 12 , 15 and 21 ....

We need to find their factors ... So ,

12 = 2 × 2 × 3

15 = 3 × 5

21 = 3 × 7

Here , HCF = 3

Then , LCM = 2 × 2 × 5 × 7 × 3

LCM = 420