Year 9 Mathematics – Term 4 (WA Curriculum): Advanced Number Systems and Geometric Applications

What this unit covers

In Term 4, Year 9 Mathematics in the WA Curriculum centres on the unit “Advanced Number Systems and Geometric Applications”.

Students explore very large and small numbers in scientific notation, extend algebraic skills with indices and equations, and apply geometric principles including trigonometry and measurement to real-world contexts.

Lesson sequence (30 lessons)

The unit breaks down into the following lesson-by-lesson sequence — each title below is a teachable lesson, in order:

1. Exploring Very Large Numbers in Real-World Contexts
2. Investigating Very Small Numbers and Their Applications
3. Converting Between Standard Form and Scientific Notation
4. Comparing and Ordering Numbers in Scientific Notation
5. Understanding Exact vs Approximate Solutions
6. Applying Pythagoras' Theorem with Exact and Approximate Answers
7. Extending Index Laws to Positive Integer Indices
8. Simplifying Expressions Using the Zero Index
9. Exploring Negative Indices and Fractional Equivalents
10. Converting Between Negative Indices and Decimals
11. Factoring Algebraic Expressions with Like Terms
12. Applying the Distributive Law to Algebraic Factors
13. Expanding Binomial Products Using the Distributive Law
14. Collecting Like Terms in Binomial Expansions
15. Solving Linear Equations with Brackets
16. Solving Linear Equations with Variables on Both Sides
17. Exploring Solutions to Quadratic Equations of the Form x² = k
18. Verifying Solutions by Substitution
19. Finding Distance Between Two Points on the Cartesian Plane
20. Calculating Gradient and Midpoint of Line Segments
21. Graphing Linear Equations in ax + by = c Form
22. Interpreting Gradient and y-intercept in Linear Relationships
23. Solving Direct Proportion Problems in Context
24. Graphing and Solving Simple Quadratic Equations
25. Calculating Income Tax and Superannuation from Pay Slips
26. Applying Simple Interest Formula to Loans and Savings
27. Solving Real-World Problems with Scientific Notation
28. Calculating Perimeter and Area of Complex Shapes
29. Applying Pythagoras' Theorem to Determine Right-Angled Triangles
30. Using Trigonometric Ratios to Find Unknown Sides and Angles

Curriculum codes in this unit

Content codes:

Reading the codes: WA codes (the ones starting with WA) pack the year level, learning area, strand and content number into one string, while the national Australian Curriculum v9 uses a different anatomy that starts with AC9 — same content family, different labels. Our complete WA Curriculum guide decodes both, character by character.

Planning notes for Term 4

WA terms run roughly 9–11 weeks, and in 2026 Term 4 runs from Monday 12 October to Thursday 17 December — 10 weeks for WA public schools. With 30 lessons in this unit, that leaves breathing room for assessment, moderation and the weeks that disappear to carnivals, camps and public holidays — plan the assessable work to land two to three weeks before the end of term rather than in the final week.