Simplifying Algebraic Fractions (Cambridge (CIE) IGCSE International Maths): Revision Note

Exam code: 0607

Jamie Wood

Written by: Jamie Wood

Reviewed by: Dan Finlay

Updated on

Simplifying Algebraic Fractions

What is an algebraic fraction?

  • A fraction with a numerator or denominator (or both) that contains an algebraic term is an algebraic fraction

  • For example

    • x over 4 or 48 over y squared or fraction numerator 2 p cubed over denominator 4 p squared plus 1 end fraction

  • You need to be able to simplify basic algebraic fractions

    • Like x to the power of 5 over x squared or fraction numerator 3 over denominator 6 p end fraction

How do I simplify algebraic fractions?

  • To simplify any powers (indices) it helps to write out the multiplications in full

    • n to the power of 5 over n squared equals fraction numerator n cross times n cross times n cross times n cross times n over denominator n cross times n end fraction

  • Terms can then be "cancelled"

    • n to the power of 5 over n squared equals fraction numerator n cross times n cross times n cross times up diagonal strike n cross times up diagonal strike n over denominator up diagonal strike n cross times up diagonal strike n end fraction equals n cross times n cross times n equals n cubed

    • m squared over m cubed equals fraction numerator m cross times m over denominator m cross times m cross times m end fraction equals fraction numerator up diagonal strike m cross times up diagonal strike m over denominator m cross times up diagonal strike m cross times up diagonal strike m end fraction equals 1 over m

  • Any numerical fractions can be simplified as usual

    • 4 over 12 equals 2 over 6 equals 1 third

  • You also need to be familiar with alternative ways of writing fractions

    • fraction numerator 3 x over denominator 4 end fraction is the same as 3 cross times x over 4 or 3 over 4 x or 0.75 x

    • fraction numerator 5 over denominator 6 y end fraction is the same as 5 cross times fraction numerator 1 over denominator 6 y end fraction or 5 over 6 cross times 1 over y

Worked Example

Simplify the following expressions.

(a) fraction numerator 4 p cubed over denominator 12 p to the power of 6 end fraction

Separate the numerical part from the algebraic part

4 over 12 cross times p cubed over p to the power of 6

Simplify the numerical fraction

1 third cross times p cubed over p to the power of 6

Write out the algebraic terms in full

1 third cross times fraction numerator p cross times p cross times p over denominator p cross times p cross times p cross times p cross times p cross times p end fraction

Cancel any terms that appear in both the numerator and denominator

1 third cross times fraction numerator up diagonal strike p cross times up diagonal strike p cross times up diagonal strike p over denominator p cross times p cross times p cross times up diagonal strike p cross times up diagonal strike p cross times up diagonal strike p end fraction

1 third cross times fraction numerator 1 over denominator p cross times p cross times p end fraction

Simplify

1 third cross times 1 over p cubed

Combine into one term

fraction numerator bold 1 over denominator bold 3 bold italic p to the power of bold 3 end fraction

(b) fraction numerator 32 q to the power of 5 over denominator 8 q squared end fraction

Separate the numerical part from the algebraic part

32 over 8 cross times q to the power of 5 over q squared

Simplify the numerical fraction

4 cross times q to the power of 5 over q squared

Write out the algebraic terms in full

4 cross times fraction numerator q cross times q cross times q cross times q cross times q over denominator q cross times q end fraction

Cancel any terms that appear in both the numerator and denominator

4 cross times fraction numerator q cross times q cross times q cross times up diagonal strike q cross times up diagonal strike q over denominator up diagonal strike q cross times up diagonal strike q end fraction

4 cross times q cross times q cross times q

Simplify

bold 4 bold italic q to the power of bold 3

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Jamie Wood

Author: Jamie Wood

Expertise: Maths Content Creator

Jamie graduated in 2014 from the University of Bristol with a degree in Electronic and Communications Engineering. He has worked as a teacher for 8 years, in secondary schools and in further education; teaching GCSE and A Level. He is passionate about helping students fulfil their potential through easy-to-use resources and high-quality questions and solutions.

Dan Finlay

Reviewer: Dan Finlay

Expertise: Maths Subject Lead

Dan graduated from the University of Oxford with a First class degree in mathematics. As well as teaching maths for over 8 years, Dan has marked a range of exams for Edexcel, tutored students and taught A Level Accounting. Dan has a keen interest in statistics and probability and their real-life applications.