Question

find the HCF ma LCM using the prime factorisation method 18and45​

Answer 1

Answer:

Express 18 and 45 as product of primes. 

18=2×3×3×=2×32

45=3×3×5=32×5

∴ HCF of 18 and 45=3×3=9

LCM of 18 and 45=3×3×2×5=90

Recall : HCF of any 2 positive integers is the product of the smallest power of each common prime factor of the numbers. 

LCM of any 2 positive integers is the product of the greatest power of each factor of the numbers.