Grade 9 Mathematics Study Guide – Lebanese Curriculum

Grade 9 Mathematics is the most decisive Brevet subject for many students: it has a high coefficient, and its exercises reward method as much as knowledge. The programme brings together everything from the intermediate cycle — numbers, algebra, geometry, statistics and functions — and asks students to combine them in multi-step exercises.

This guide walks through the main blocks of the Grade 9 programme, what to master in each, and how to revise them efficiently.

Numbers, powers and radicals

Rational and irrational numbers, scientific notation, powers with integer exponents, and square roots: simplifying radicals (√50 = 5√2), rationalising denominators, and using the rules √a·√b = √(ab). Most errors here come from sign mistakes and from applying power rules to sums. Practise short drills until the rules are automatic.

Algebraic expressions and factorisation

Expanding with the remarkable identities (a+b)², (a−b)², (a+b)(a−b), and factorising back. Grade 9 exercises often ask you to expand, then factorise, then solve — the same expression used three ways. Learn to recognise a difference of squares and a perfect square at a glance.

Equations, inequalities and systems

First-degree equations and inequalities (with the sign flip when multiplying by a negative), product equations (A·B = 0), and systems of two linear equations solved by substitution or elimination. Word problems translate a story into a system: define the unknowns explicitly and check the answer against the story.

Geometry: Pythagoras, Thales and trigonometry

The Pythagorean theorem and its converse, the Thales theorem (proportional segments in a triangle cut by a parallel) and its converse, and the trigonometric ratios sine, cosine and tangent in a right triangle. Draw the figure yourself, mark what is given, and state the theorem in full before computing — examiners award marks for the statement.

Vectors, coordinates and transformations

Coordinates of points and vectors, distance between two points, midpoint, collinearity, and translations. Keep a checklist: write the vector formula, substitute carefully, and simplify radicals in distances.

Statistics and functions

Frequency tables, mean, median and mode; proportionality and linear functions (y = ax and y = ax + b), reading and drawing graphs. Questions often combine a table with a graph — practise moving between the two.

How to revise Grade 9 Math

Per chapter: lesson → 20 practice questions with explanations → timed chapter exam. Target 80%.
Keep a one-page formula sheet (identities, Pythagoras, Thales, trig ratios, distance, midpoint).
Do mixed sets weekly from March; the Brevet mixes chapters in one exercise.
Write full solutions even for MCQ practice — method is where marks are lost.

Questions students ask

Which Grade 9 Math chapters carry the most weight?

Algebra (identities, equations, systems) and geometry (Pythagoras, Thales, trigonometry) appear in almost every paper; statistics and functions are shorter but reliable marks.

How many questions should I practise per chapter?

Around 20 practice questions plus one timed exam per chapter, and a second exam later for the chapters below 80%.

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