Using prime factorization, find the HCF and LCM of:

i. 36, 84 ii. 23, 31


iii. 96, 404 iv. 144, 198


v. 396, 1080 vi. 1152, 1664


In each case, verify that:


HCF x LCM = product of given numbers.

i. HCF = 12, LCM = 252


Prime factorization of given numbers -


36 = 2 × 2 × 3 × 3


84 = 2 × 2 × 3 × 7


So HCF = product of common factors = 2 × 2 × 3 = 12


And LCM = product of prime factors with highest powers = 22 × 32 × 7 = 252


Verification -


HCF × LCM = product of numbers


LHS = 12 × 252 = 3024


RHS = 36 × 84 = 3024


LHS = RHS(Hence verified)


ii. HCF = 1, LCM = 713


Prime factorization of given numbers -


23 = 23 × 1


31 = 31 × 1


So HCF = product of common factors = 1


And LCM = product of prime factors with highest powers = 23 × 31 = 713


Verification -


HCF × LCM = product of numbers


LHS = 1 × 713 = 713


RHS = 23 × 31 = 713


LHS = RHS(Hence verified)


iii. HCF = 4, LCM = 9696


Prime factorization of given numbers -


96 = 2 × 2 × 2 × 2 × 2 × 3


404 = 2 × 2 × 101


So HCF = product of common factors = 2 × 2 = 4


And LCM = product of prime factors with highest powers = 25 × 3 × 101 = 9696.


Verification -


HCF × LCM = product of numbers


LHS = 4 × 9696 = 38784


RHS = 96 × 404 = 38784


LHS = RHS(Hence verified)


iv. HCF = 18, LCM = 1584


Prime factorization of given numbers -


144 = 2 × 2 × 2 × 2 × 3 × 3


198 = 2 × 3 × 3 × 11


So HCF = product of common factors = 2 × 3 × 3 = 18


And LCM = product of prime factors with highest powers = 24 × 32 × 11 = 1584


Verification -


HCF × LCM = product of numbers


LHS = 18 × 1584 = 28512


RHS = 144 × 198 = 28512


LHS = RHS(Hence verified)


v. HCF = 36, LCM = 11880


Prime factorization of given numbers -


396 = 2 × 2 × 3 × 3 × 11


1080 = 2 × 2 × 2 × 3 × 3 × 3 × 5


So HCF = product of common factors = 2 × 2 × 3 × 3 = 36


And LCM = product of prime factors with highest powers = 23 × 33 × 5 × 11 = 11880


Verification -


HCF × LCM = product of numbers


LHS = 36 × 11880 = 427680


RHS = 396 × 1080 = 427680


LHS = RHS(Hence verified)


vi. HCF = 128, LCM = 14976


Prime factorization of given numbers -


1152 = 2 × 2 × 2 × 2 × 2 × 2 × 2 × 3 × 3


1664 = 2 × 2 × 2 × 2 × 2 × 2 × 2 × 13


So HCF = product of common factors = 2 × 2 × 2 × 2 × 2 × 2 × 2 = 128


And LCM = product of prime factors with highest powers = 27 × 32 × 13 = 14976


Verification -


HCF × LCM = product of numbers


LHS = 128 × 14976 = 1916928


RHS = 1152 × 1664 = 1916928


LHS = RHS(Hence verified)


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