Prime Factors - GCSE Maths Definition

Reviewed by: Jamie Wood

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What are prime factors?

In GCSE maths, prime factors are the prime numbers which multiply to give that number. For example, the prime factors of 12 are 2 and 3. This is because 12 can be written as 2×2×3. The prime factors of 30 would be 2, 3 and 5, as 30 can be written as 2×3×5.

The process of writing a number as a product of its prime factors is known as prime factor decomposition. Read our revision note about prime factor decomposition to find out more.

What is a prime number?

A prime number is a number which has exactly two factors, itself and 1. Remember that 1 is not a prime number, as it only has one factor. You should remember at least the first ten prime numbers: 2, 3, 5, 7, 11, 13, 17, 19, 23, 29.

Prime factors revision resources to ace your exams

Learn more about types of numbers and prime factor decomposition with our revision notes. To test your knowledge, try our prime factors, HCF & LCM exam questions.

For quick-fire GCSE maths revision use our collection of interactive flashcards for GCSE maths. We also have past papers for your exam practice.

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Need help reaching your target grade? Explore our notes, questions by topic and worked solutions, tailor-made for GCSE Maths.

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Jamie Wood

Reviewer: Jamie Wood

Expertise: Maths Content Creator

Jamie graduated in 2014 from the University of Bristol with a degree in Electronic and Communications Engineering. He has worked as a teacher for 8 years, in secondary schools and in further education; teaching GCSE and A Level. He is passionate about helping students fulfil their potential through easy-to-use resources and high-quality questions and solutions.

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