This nine-lesson simplifying expressions PowerPoint takes students from the most basic simplifying up through substitution and proof of formulae.

The lessons focus on these questions. Can I:

• decide whether I have a formula, an equation or an expression?
• simplify expressions by joining ‘like terms’?
• substitute values into a formula?
• simplify expressions involving brackets?
• simplify algebraic fractions by finding a common denominator?
• simplify expressions by using the rules of indices?
• write a formula for a given situation?
• rearrange formulae by using inverse operations?
• show how a formula is formed?

What’s the difference?

A formula shows you how to calculate something – it will contain an equals sign.

Eg. Area of a rectangle = length × width (A = lw)

An equation allows you to calculate the value of a letter – it contains an equals sign.

Eg. 3x + 2 = 14

An expression is just a series of letters.

Eg. 3a + 2b – 5c

Learning objectives

• Decide whether something is an equation, expression or formula
• Substitute numbers into given formulae
• Multiply out brackets and simplify expressions
• Simplify simple algebraic fractions
• Simplify expressions using rules of indices
• Write a formula for a given situation
• Rearrange formulae by using inverse functions
• Use and show how formulae are derived

KS3 maths curriculum area

Algebra: Substitute numerical values into formulae and expressions, including scientific formulae

Andy Lutwyche is a purveyor of mathematics and a producer of resources, more of which you can find on his TES shop. You can also follow him on Twitter at @andylutwyche.

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