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Year 9 - Maths

Features of special number sequences

Non-linear relationships

Unit Summary

In this unit we explore geometric and special number sequences like the Fibonacci sequence. We develop strategies to recognise types of sequence and continue them.

Lesson Summary

You will learn to appreciate the features of special number sequences, such as square, triangular and cube.

Key Notes

  • Square number sequences are formed by squaring the position within the sequence.
  • Cube number sequences are formed by cubing the position within the sequence.
  • Triangular number sequences are formed by increasing the difference by one between each consecutive term.
  • These special number sequences can be represented visually.

Vocabulary To Learn

  • Triangular number: A triangular number is a number that can be represented by a pattern of dots arranged into an equilateral triangle. The term number is the number of dots in a side of the triangle

Common Mistakes To Avoid

  • Square numbers are any number that can be squared.

3 Quick Questions (With Answers)

1. Solve this in steps: explain the method from this lesson and why each step matters.

Square number sequences are formed by squaring the position within the sequence. Cube number sequences are formed by cubing the position within the sequence.

2. Use this key word in a maths sentence and explain it clearly. 'Triangular number'

A triangular number is a number that can be represented by a pattern of dots arranged into an equilateral triangle. The term number is the number of dots in a side of the triangle. Use this word when showing your method, then check your final answer is reasonable.

3. Spot and fix this common maths mistake.

Mistake: Square numbers are any number that can be squared. Correction: Give students counters or let them draw dot patterns to explore square numbers geometrically as well as numerically.

More Lessons In This Unit

Browse all guides in the Year 9 Maths guide library.