Junior Cycle · Number Theory Lesson 2 of 5

JCHL Number Theory 2: Prime Factorisation

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You’ll learn

  • Every natural number is a product of prime numbers
  • Divide by the smallest prime that goes in (2, then 3, then 5, 7, 11…), again and again, until you reach 1
  • Write the answer as a product of primes, using powers for repeats (e.g. 420 = 2² × 3 × 5 × 7)

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