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.
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