Answer:
Below in bold.
Step-by-step 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.
