Year 9 Maths

Free interactive notes for every chapter of NSW Year 9 Maths: financial maths, equations and simultaneous equations, Pythagoras and trigonometry, linear graphs, surface area and volume, indices and surds, similar figures, quadratics, probability and statistics, and parabolas.

1Pick a chapter below.
2Notes: learn with clear examples, interactive graphs and flashcards.
3Practice: every section ends with questions that mark themselves, plus unlimited extra questions.

Year 9 starts Stage 5. It builds on the Year 8 Maths notes and introduces trigonometry, simultaneous equations, factorising quadratics and parabolas, the skills that lead into Years 10, 11 and 12. Tap Mark as mastered after each section to track your progress on this device. No account needed.

Chapters

1 Financial mathematics 4 sections

Percentage increase and decrease, profit, loss and discounts, wages, salaries, overtime, commission and income tax, simple interest, compound interest and depreciation.

Notes Quizzes
2 Expressions, equations and simultaneous equations 5 sections

Expanding and simplifying expressions, solving harder linear equations, equations of the form ax² = c, inequalities, rearranging formulas, and solving simultaneous equations by substitution, elimination and graphing.

Notes Quizzes
3 Pythagoras and trigonometry 6 sections

Pythagoras' theorem in two and three dimensions, the sine, cosine and tangent ratios, finding unknown sides and angles, angles of elevation and depression, and bearings.

Notes Quizzes
4 Linear relationships 5 sections

Graphing straight lines with intercepts, horizontal and vertical lines, gradient and y = mx + c, finding the equation of a line, midpoint and distance, and parallel and perpendicular lines.

Notes Quizzes
5 Length, area, surface area and volume 5 sections

Circumference, arc length and sector perimeters, areas of composite shapes, circles and sectors, surface area of prisms, pyramids and cylinders, and volume of prisms and cylinders.

Notes Quizzes
6 Indices and surds 5 sections

Index laws for multiplying, dividing and powers, zero and negative indices, scientific notation and significant figures, fractional indices, and simplifying and operating with surds.

Notes Quizzes
7 Geometry: congruence and similarity 4 sections

Angle facts for parallel lines, triangles and polygons, properties of quadrilaterals, congruence tests and simple proofs, enlargement, and similar triangles with their applications.

Notes Quizzes
8 Quadratic expressions and algebraic fractions 4 sections

Expanding binomial products, perfect squares and difference of two squares, factorising with common factors, grouping, monic and non-monic trinomials, and simplifying, multiplying, dividing, adding and subtracting algebraic fractions.

Notes Quizzes
9 Probability and statistics 4 sections

Venn diagrams, two-way tables and set notation, two-step experiments with arrays and tree diagrams, measures of centre from frequency tables and grouped data, and measures of spread with quartiles, interquartile range and box plots.

Notes Quizzes
10 Quadratic equations and parabolas 5 sections

Solving quadratic equations by factorising and the null factor law, worded quadratic problems, features of parabolas, transformations of y = x², and sketching parabolas from intercepts and turning points.

Notes Quizzes