Paper 1 · Number Theory ⏱ Tested in 1 exam question since 2023 Lesson 2 of 5

Number Theory 2 – Prime Factorisation

This tutorial is for members

Read the lesson notes free below — subscribe to watch the full worked video and download the PDF.

Subscribe for full access · €199/yr

You’ll learn

  • Write any natural number as a product of primes with the division ladder
  • Group repeated primes as powers, e.g. 2 × 2 × 3 × 5 × 7 = 2² × 3 × 5 × 7
  • Find the HCF and LCM of large numbers using the Venn-diagram method
  • Count the divisors of N from its prime powers: d(N) = (a₁+1)(a₂+1)…

Most recent exam questions

  • 2023 P1 Q9(a)(i)
  • 2023 P1 Q9(a)(ii)
  • 2023 P1 Q9(a)(iii)

💬 Stuck on something in this lesson?

Send your question with this lesson’s name attached — you’ll get a reply by email.