Factor Trees
Maths: Year 5 & 6 National Curriculum, topic 1.3.6
Prime Factor Trees
Prime factor trees can help us determine what the prime factors of a number are.
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Making a prime factor tree
- A prime factor tree breaks numbers up into their factor.
- Let's make a factor tree for 24.
- Start by selecting one factor pair of 24 (e.g. 3 and 8)
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Are they prime numbers?
- If either of the factors are prime numbers, you stop going down that branch.
- You should circle that number so you remember it is a prime number.
- If the factor is a composite number, then continue splitting it up into a factor pair.
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Split any composite numbers
- You need to continue to split any composite numbers into their factors.
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Continue until prime
- You should continue splitting the composite numbers until you get to prime numbers on all branches of your factor tree.
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Prime factors of 24
- The factor tree tells you that the prime factors of 24 are 2, 2, 2 and 3.
- The prime factors of 24 are 2, 2, 2 and 3 because 2 × 2 × 2 × 3 = 24.