Prime Factors

Decompose a number into prime factors using a factor tree, then express the result in product form and index form.

 All resources Download All ⬇

Te reo Māori terms

click each term to open in Te Aka

Related resources in Number

Learning objective overview

Master Teaching Guide coverage for this objective.

Resources

Terminology

  • prime number
  • factors
  • factor tree
  • product form (for example, 2 x 2 x 2 x 2 x 5)
  • index form (for example, 2^4 x 5)

Task goals

  • Identify which numbers in a given list are prime.
  • Write a given number as a product of prime factors using a factor tree.
  • Complete a partially-filled prime factorisation by finding the missing factor(s).
  • Write a number's prime factorisation in index form.
  • Choose which of two given expressions is the correct prime factorisation of a number, or judge whether a stated factorisation is valid and explain why.
  • Find the original number from its prime factorisation given in index form, and verify a stated factorisation is correct by multiplying the factors back together.
  • Compare the prime factorisations of two numbers to determine which number is larger, or find a missing exponent or factor in a partially-given factorisation.
  • Explain, using a worked example, why a composite number has only one possible set of prime factors.

Key skills

  • Prime factorisation
  • Factor trees
  • Index form

Quick stats

  • 81 total questions
  • 3 difficulty levels
  • Answers included
Open terms PDF
Open tasks PDF
Open tasks PDF
Open tasks PDF

For teachers

Need the fuller teaching notes for this objective? Open the Teacher guidance PDF.