Key Stage 3 — Expressions, Equations and Formulae — scheme of work

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Key Stage 3: Expressions, Equations and Formulae Scheme of Work

This Key Stage 3 Expressions, Equations and Formulae scheme of work is designed for Year 8 work on expanding and factorising algebraic expressions, substituting into formulae, solving linear equations including those with unknowns on both sides and with fractions, changing the subject of a formula, and an introduction to factorising quadratics.

Use this page to sequence the lessons below, keep expanding and factorising vocabulary distinct, and build from single-bracket work through to two-bracket expansion and quadratic factorisation before students encounter formal algebraic proof.

For more schemes and topic routes across KS3, GCSE and A-Level, browse the Mr Mathematics Curriculum Hub.

How to use this scheme

Read the prerequisite and key-concept cards first so algebraic notation, collecting like terms and single-bracket work are secure. Teach the lessons in the order listed unless your timetable requires otherwise — keep single-bracket expansion and substitution before two-bracket work, and equations with unknowns on both sides before equations with fractions.

Mr Mathematics membership

Presentations, worksheets, question generators and video tutorials for the lessons in this unit are available to members. Explore Mr Mathematics membership if you need full access to the library and schemes of work.

If you are comparing options for a department, the membership page sets out exactly what is included so you can align this unit with your wider KS3 algebra plan.

Prerequisite knowledge

Students should be secure with the following before this unit.

  • Use and interpret algebraic notation, including:
    • ab in place of a × b
    • 3y in place of y + y + y and 3 × y
    • a² in place of a × a, a³ in place of a × a × a; a²b in place of a × a × b
    • a/b in place of a ÷ b
  • Write coefficients as fractions rather than decimals.
  • Simplify and manipulate algebraic expressions to maintain equivalence by collecting like terms.

Key concepts

Ideas to keep explicit while students work with expressions, equations and formulae.

  • Expanding brackets means removing the brackets; factorising an expression means putting it into brackets.
  • When expanding brackets by a negative, every term inside the bracket must be multiplied by the negative.
  • When factorising, use the highest common factor of each term. A common error is to only partially factorise — for example, 9a + 12a² is fully factorised as 3a(3 + 4a), not a(9 + 12a).
  • When solving equations involving brackets it is not always necessary to expand first; dividing both sides by the number outside the bracket is often more efficient.
  • To solve an equation, collect like terms so all the unknowns are on one side before isolating the variable.
  • When substituting known values into a formula, apply the correct order of operations. Take care with negative and fractional values.
  • A formula has the subject isolated on one side. Use the balance method and order of operations to change the subject.

Subject content (Algebra)

  • Substitute numerical values into formulae and expressions, including scientific formulae.
  • Understand and use the concepts and vocabulary of expressions, equations, inequalities, terms and factors.
  • Simplify and manipulate algebraic expressions to maintain equivalence by: collecting like terms; multiplying a single term over a bracket; taking out common factors; expanding products of two or more binomials.
  • Understand and use standard mathematical formulae; rearrange formulae to change the subject.
  • Use algebraic methods to solve linear equations in one variable (including all forms that require rearrangement).

Working mathematically

How this unit supports fluency, reasoning and problem solving in Key Stage 3.

  • Develop fluency
    • Use algebra to generalise the structure of arithmetic, including to formulate mathematical relationships.
    • Substitute values in expressions, rearrange and simplify expressions, and solve equations.
  • Reason mathematically
    • Identify variables and express relations between variables algebraically and graphically.
  • Solve problems
    • Develop mathematical knowledge, partly through solving problems and evaluating the outcomes, including multi-step problems.
    • Select appropriate concepts, methods and techniques to apply to unfamiliar and non-routine problems.

Common misconceptions

Typical slips to address during teaching and marking.

  • Multiplying only the first term inside a bracket when the multiplier outside is negative, rather than applying it to every term.
  • Partially factorising by taking out a common factor that is not the highest — for example writing a(9 + 12a) instead of 3a(3 + 4a).
  • Assuming brackets must always be expanded before solving an equation, rather than dividing both sides by the coefficient outside the bracket.
  • Sign errors when substituting negative or fractional values, particularly when squaring a negative or applying BIDMAS with fractions.
  • Failing to collect all like terms before isolating the unknown when the variable appears on both sides of an equation.

Frequently asked questions

How do I use this scheme page in practice?

Use it to sequence teaching, align vocabulary and spot likely errors before they become habits. Then use the lessons below as the delivery route for the unit.

What should students already know before this unit?

They need confident algebraic notation, the ability to collect like terms and experience of single-bracket expansion so new work focuses on two-bracket products, factorisation strategies and solving more complex equations rather than basic notation.

Where are the lesson presentations and worksheets?

Each lesson listed below has its own page with downloadable resources and, where available, online tasks. Access depends on your membership level.

Can I change the order of the lessons?

Yes if your timetable requires it — keep single-bracket expansion and substitution before two-bracket work, and place equations with fractions and changing the subject after students can solve equations with unknowns on both sides confidently.

Where can I find revision resources for this topic?

Additional revision lessons, exam-style questions and topic-based practice are available on the GCSE Maths Revision Hub. This is useful for consolidating learning after teaching the unit or for Year 11 exam preparation.

Lessons in this Expressions, Equations and Formulae scheme of work

  • Multiplying out Algebraic Brackets
  • Substituting Numbers into Formulae
  • Expanding Brackets and Collecting Like Terms
  • Factorising Expressions into a Pair of Brackets
  • Expanding Two Brackets
  • Solving Equations with the Unknown on Both Sides
  • Solving Linear Equations with Fractions
  • Setting Up Complex Equations
  • Changing the Subject of a Formula
  • Factorising Quadratics

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