Question

How to find the hcf and the lcm of numbers using prime factorization.

lcm
30 and 12.

hcm
12 and 20​

Answer 1

Below in bold.

Explanation:

30 = 2 * 3 * 5

12 = 2 * 2 * 3

Note that 2 and 3 are common to both factors

so the HCF = 2*3 = 6.

Only one 2 and one 3 of the duplicates are included in the LCM:

so the LCM = 2 * 3 * 2 * 5 = 60

20 = 2 * 2 * 5

12 = 2 * 2 * 3

HCF = 2 *2 = 4

LCM = 2*2*3*5 = 60.