Year 7 - Maths
Representing an unknown or variable
Expressions and equations
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This pupil-friendly study guide includes a unit summary, clear notes, common mistakes, and quick questions with answers.
Unit Summary
In this unit, pupils learn about generalisation and formal algebraic manipulation techniques such as substitution, collecting like terms and factorising.
Lesson Summary
You will learn to recognise that a letter can be used to represent a specific unknown or a variable and know the difference.
Key Notes
- A letter can be used to represent a specific unknown in a variety of ways.
- A letter can be used to represent a variable in a number of ways.
- It is possible to tell the difference between letters representing unknowns or variables
Vocabulary To Learn
- Unknown: An unknown is a quantity that has a set value but is represented by a symbol or letter.
- Variable: A variable is quantity that can take on a range of values.
- Formula: A formula is a rule linking sets of physical variables in context. The plural of formula is formulae.
Common Mistakes To Avoid
- Pupils may think that letters always represent a set value that can be 'found'.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
A letter can be used to represent a specific unknown in a variety of ways. A letter can be used to represent a variable in a number of ways.
2. Use this key word in a maths sentence and explain it clearly. 'Unknown'
An unknown is a quantity that has a set value but is represented by a symbol or letter. Use this word when showing your method, then check your final answer is reasonable.
3. Spot and fix this common maths mistake.
Mistake: Pupils may think that letters always represent a set value that can be 'found'. Correction: Highlight the distinction between unknowns and variables. Allow pupils to explore expressions intrinsically before substituting in values.
More Lessons In This Unit
- Algebraic notation Study Guide
- Algebraic terminology Study Guide
- Checking understanding of expressions and equations Study Guide
- Factorising expressions Study Guide
- Generalised algebraic statements Study Guide
- Highest common factor with algebraic terms Study Guide
- Like terms Study Guide
- Multiplying an expression by a constant Study Guide
- Multiplying an expression by a term Study Guide
- Multiplying and simplifying with multiple expressions Study Guide
- Problem solving with expressions and equations Study Guide
- Representing a generalised number Study Guide
- Securing understanding of expressions and equations Study Guide
- Simplifying before multiplying with multiple expressions Study Guide
- Simplifying by collecting like terms Study Guide
- Substituting particular values Study Guide
Browse all guides in the Year 7 Maths guide library.