Growing Patterns
Growing patterns form the backbone of algebraic thinking in Key Stage 2 and 3, helping students recognise mathematical relationships before they encounter formal algebra. When Year 5 pupils spot that 3, 6, 10, 15 follows the triangular number sequence, they're developing pattern recognition skills that will serve them through GCSE mathematics.
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Why it matters
Pattern recognition underpins mathematical reasoning across all areas. In real life, growing patterns appear everywhere: a football league table where teams earn 3 points per win follows an arithmetic sequence, whilst savings accounts with compound interest follow exponential patterns. Students who master pattern analysis in primary school find algebraic expressions and sequences much easier at GCSE level. The ability to spot that 2, 6, 18, 54 multiplies by 3 each time prepares pupils for geometric sequences in Year 10. Even simple contexts like calculating bus fares (£2.50, £5.00, £7.50 for 1, 2, 3 zones) or planning school fundraising events rely on pattern recognition. These foundational skills support mathematical modelling, where students must identify relationships between variables and make predictions based on observed trends.
How to solve growing patterns
Pattern Structures
- A pattern has a rule. Find what stays the same and what changes.
- Describe the rule in words first, then in symbols or numbers.
- Test the rule on the next term: does it predict correctly?
- Extend the pattern both forwards and backwards to check.
Example: 1, 4, 9, 16, ... The rule is square the position: 1², 2², 3², 4². Next: 5² = 25.
Worked examples
What comes next? 10, 12, 14, 16, 18, ?
Answer: 20
- Find the difference between consecutive terms → 12 - 10 = 2 — Each number increases by 2.
- Add the difference to the last term → 18 + 2 = 20 — The next number is 18 + 2 = 20.
What comes next? 1, 3, 6, 10, ?
Answer: 15
- Find the differences between consecutive terms → 2, 3, 4 — The differences are 2, 3, 4. They increase by 1 each time.
- Find the next difference and add it → 10 + 5 = 15 — The next difference is 5. So 10 + 5 = 15. These are triangular numbers.
What comes next? 2, 4, 7, 11, 16, ?
Answer: 22
- Calculate the differences between terms → 2, 3, 4, 5 — The differences are 2, 3, 4, 5. Each difference increases by 1.
- Find the next difference and add it → 16 + 6 = 22 — The next difference is 6. So 16 + 6 = 22.
Common mistakes
- Students often assume all patterns follow simple addition rules. For the sequence 1, 4, 9, 16, they might write 25, 34, 43 (adding 9 each time) instead of recognising the square number pattern where the next term is 25.
- Pupils frequently ignore changing differences in sequences. Given 2, 5, 9, 14, they might continue with 19, 24 (adding 5 repeatedly) rather than spotting that differences increase by 1 each time, making the next term 20.
- Many students struggle with position-to-term relationships. When asked to find the 10th term of 5, 8, 11, 14, they count up term by term instead of using the rule '3n + 2' to calculate 3(10) + 2 = 32.