Question

Using prime factorisation, find the HCF and LCM of 24, 36, 40.

Answer 1

24 = 2 × 2 × 2 × 3 = 2³ × 3

36 = 2 × 2 × 3 × 3 = 2² × 3²

40 = 2 × 2 × 2 × 5 = 2³ × 5

HCF = product of smallest power of each common prime factor in the numbers
= 2²

= 4

LCM = product of greatest power of each prime factor involved in the numbers

= 2³ × 3² × 5

= 360