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Year 10 - Maths

Checking and securing understanding of substitution

Algebraic manipulation

Unit Summary

In algebraic manipulation, pupils use apply knowledge of the distributive law to find the product of two binomaials in order to factorise quadratics.

Lesson Summary

You will learn to substitute particular values into a generalised algebraic statement to find a sense of how the value of the expression changes.

Key Notes

  • Expressions and formulae in context can be evaluated for particular values.
  • Changing the value of the variable changes the overall value of the expression.
  • Exploring what value gives a particular solution can help you to understand the expression.
  • Expressions may have multiple variables and you can substitute some or all of them for numbers.

Vocabulary To Learn

  • Substitution: Substitute means to put in place of another. In Algebra, substitution can be used to replace variables with values.

Common Mistakes To Avoid

  • Incorrect evaluation of expressions is common when negative values are substituted. Especially where negative values are squared or pupils rely on calculators without being confident of their use.

3 Quick Questions (With Answers)

1. Solve this in steps: explain the method from this lesson and why each step matters.

Expressions and formulae in context can be evaluated for particular values. Changing the value of the variable changes the overall value of the expression.

2. Use this key word in a maths sentence and explain it clearly. 'Substitution'

Substitute means to put in place of another. In Algebra, substitution can be used to replace variables with values. Use this word when showing your method, then check your final answer is reasonable.

3. Spot and fix this common maths mistake.

Mistake: Incorrect evaluation of expressions is common when negative values are substituted. Especially where negative values are squared or pupils rely on calculators without being confident of their use. Correction: When substituting, always put brackets around the value which is substituted. This helps avoid mistakes when using a calculator as well.

More Lessons In This Unit

Browse all guides in the Year 10 Maths guide library.