Question:What is the GCF of 20 and 30?
Factors of 20:1,2,4,5,10,20
Factors of 30:1,2,3,5,6,10,15,30
Find their common factors and find for the greatest factors
10 is your GCF.
Question:What is the LCM of 5 and 6?
Find the multiples of 5 and 6
Multiples of 5:5,10,15,20,25,30,35,........
Multiples of 6:6,12,18,24,30,36,..........
Find their common multiples and get the least number.
30 is your LCM.