Page 97 - Knowledge Organiser Yr7 24-25

Knowledge Base: Mathematics TOPIC 6: Manipulating Expressions Year 7 | Spring Term 1
By the end of this topic you should be able to:
• Use letters to stand for unknown values
• Simplify an algebraic expression by collecting like terms
• Simplify an algebraic expression with multiplied or divided terms
• Use indices to simplify expressions
• Expand brackets in an expression
• Factorise an expression
• Substitute values into expressions
Language
Meaning
Example
Expression
A series of letters andnumbers in algebra
2x + 3y
Term
Part of an expression, separated by + or – signs
In the expression 2x + 3y the terms are 2x and 3y
Like Terms
Like terms have the same combinations of letters in them
3xy and 5xy are like terms but 3xy and 3x are not
Simplify
Collect like terms in an algebraic expression
2a + 6a = 8a
Index (Plural Indices)
Another name for a power such as ‘squared’ or ‘to the power of 5’
5 is the index in x5
Substitute
To replace a letter in an algebraic expression with a number
Substituting x = 2 into 3x – 1 gives 3 × 2 – 1
Expand
To multiply out a bracket in algebra
2(3a + 1) = 6a + 2
Factorise
The reverse of expanding a bracket by taking out common factors
6x + 12y = 6(x + 2y)
Important things to remember:
1) In maths A (capital letter) and a (lower case) are different things! Check the letters in the question
2) Don’t write 1a, just write a
3) We don’t write + – in algebra, just –
4) Remember that BIDMAS still applies in algebra 5) b + b + b = 3b
6) b x b x b = b3c
Worked examples
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