Year 9 - Maths
Difference of two squares
Expressions and formulae
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This pupil-friendly study guide includes a unit summary, clear notes, common mistakes, and quick questions with answers.
Unit Summary
This unit develops pupil understanding of formulae and how to rearrange them. Pupils will learn how to recognise and manipulate binomials and learn to recognise the difference of two squares.
Lesson Summary
You will learn to use the special case when the product of two binomials is the difference of two squares.
Key Notes
- The product of two binomials often produces three terms.
- There are cases where the coefficient of the linear term is zero.
- The terms in the two binomials can indicate this.
- You can use an area model to explore the structure.
Vocabulary To Learn
- Partial product: A partial product refers to any of the multiplication results that lead up to an overall multiplication result.
- Binomial: A binomial is an algebraic expression representing the sum or difference of exactly two unlike terms.
Common Mistakes To Avoid
- Squaring a binomial is the same as just squaring each term. This can then cause confusion with difference of two squares where expanding a pair of binomials does result in just two terms.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
The product of two binomials often produces three terms. There are cases where the coefficient of the linear term is zero.
2. Use this key word in a maths sentence and explain it clearly. 'Partial product'
A partial product refers to any of the multiplication results that lead up to an overall multiplication result. Use this word when showing your method, then check your final answer is reasonable.
3. Spot and fix this common maths mistake.
Mistake: Squaring a binomial is the same as just squaring each term. This can then cause confusion with difference of two squares where expanding a pair of binomials does result in just two terms. Correction: Using an area model and taking time to check the partial products each time, particularly with negative terms, should help students to check if they have expanded correctly.
More Lessons In This Unit
- Additive relationships Study Guide
- Changing the subject to suit the context Study Guide
- Changing the subject with more complex formula Study Guide
- Changing the subject with simple formula Study Guide
- Checking and securing solving linear equations Study Guide
- Checking and securing understanding of the distributive law with algebraic terms Study Guide
- Evaluating expressions with and without changing the subject Study Guide
- More complex binomial products Study Guide
- Multiplicative relationships between terms Study Guide
- Problem solving with expressions and formulae Study Guide
- The product of two binomials Study Guide
Browse all guides in the Year 9 Maths guide library.