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GCSE Maths | HCF and LCM

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Working out the prime factors of a number

Working out the LCM of two numbers

  • find the prime factors of both numbers
  • add all the numbers to a Venn diagram
  • multiply every number
  • check it is correct by dividing by each number

Working out the HCF of two numbers

  • find the prime factors of both numbers
  • add all the numbers to a Venn diagram
  • multiply every number in the intersection (middle)
  • check it is correct by dividing each number by your answer

Question 2

a) Find the HCF and LCM of 36 and 48.

b) Find the HCF and LCM of 54 and 72.

c) Find the HCF and LCM of 60 and 84.

d) Find the HCF and LCM of 75 and 90.

e) Find the HCF and LCM of 96 and 112.

f) Find the HCF and LCM of 120 and 150.

g) Find the HCF and LCM of 144 and 180.

h) Find the HCF and LCM of 81 and 108.

i) Find the HCF and LCM of 100 and 125.

j) Find the HCF and LCM of 168 and 196.