Using prime factors
to find
the HCF and LCM
REVIEWING NUMBER CONCEPTS
Large numbers

Dealing with large numbers

Hard to spot HCF and LCM

Split number to tiny pieces

These are prime factors
49827508138750345
38598230958173435
168 = 2 X 2 X 2 X 3 X 7
Find HCF and LCM of 168 and 180
180 = 2 X 2 X 3 X 3 X 5
ALL THE COMMON FACTORS
Worked Example
2 X 2 X 3 = 12 HCF
ALL FACTORS TOGETHER
2 X 2 X 2 X 3 X 3 X 5 X 7 = 2520 LCM