Algebraic Expressions
Use letters for unknowns, collect like terms, simplify expressions and substitute numbers into expressions.
Overview
Algebra uses letters to stand for numbers we do not yet know. In Year 7 students meet expressions for the first time: they write expressions from words, collect like terms to simplify them, and substitute numbers in to find a value. This is the start of the algebra that runs all the way to IGCSE and beyond, so building good habits now is important.
What You Will Learn
- Use letters to represent unknown numbers
- Write an algebraic expression from a word description
- Simplify expressions by collecting like terms
- Simplify expressions involving multiplication, e.g. 3 × a = 3a
- Substitute positive and negative numbers into an expression to find its value
Key Vocabulary
Common Mistakes to Avoid
- Trying to add unlike terms, e.g. writing 3a + 2b = 5ab
- Writing a × a as 2a instead of a²
- Forgetting that 3a means 3 × a when substituting
- Ignoring the sign of a negative number when substituting
What Comes Next
Year 8 extends this to expanding brackets and to expressions with powers, and Year 9 reaches factorising. These skills become the IGCSE Algebra and Graphs topic.
Frequently Asked Questions
What are like terms?
Like terms use exactly the same letter or combination of letters. 3a and 5a are like terms and can be added to 8a, but 3a and 5b are not.
What does it mean to substitute?
Substituting means replacing each letter with a given number and then working out the value. If a = 4, then 3a = 3 × 4 = 12.
Study This Topic
Topic Details
- Stage
- Year 7
- Strand
- Algebra
- Framework ref
- 7Ae
- Difficulty
- Medium
Build strong foundations in Algebraic Expressions
A free trial class with Teacher Rig helps your Year 7 child master Algebraic Expressions now — so IGCSE Maths feels familiar, not frightening, later.
Heading toward IGCSE? See how Algebraic Expressions develops in IGCSE Algebra and Graphs (Cambridge 0580) →