Maths GCSE: Algebra - Formulae and Graphs

For students struggling to achieve grade 4 in GCSE maths, mathematician and comedian Matt Parker offers tips on identifying different graph types and their uses, as well as tips to avoid common mistakes when working with formulae.

We look at key problems that have been highlighted as misconceptions and sources of errors by foundation GCSE examiners.

Concentrating on solving common questions on BIDMAS, formulae and linear and quadratic graphs we highlight frequent mistakes and use the most reliable methods to solve problems. We equip students with the skills to identify and rectify errors in exam situations.

This short film is from the BBC series, The Maths Show.

Teacher Notes

Before watching

Ensure your students are happy with basic operations with algebra, including simple substitution and the four operations with negative numbers.

Students could look at plotting coordinates on a graph from a table and identifying the shape from different equations.

You could ask students to identify errors they have made in previous test papers in algebraic questions or during the lesson before watching the short film.

Whilst this short film focuses on exam technique and common errors you could also use part of it as an introduction to a new topic.

During watching

As this short film looks at different exam questions, it is simple to pause and ask students to attempt the question or share their thoughts before revealing the answer.

You could also ask students to highlight possible mistakes they might make and how to prevent them.

When discussing substituting in to expressions involving indices Matt shows how it’s easy to make a mistake if students don’t use BIDMAS correctly. Pause the video to ask students to answer the question before Matt explains the difference.

When using a table to calculate the values to plot a straight line, it may be valuable to pause to show this table. Many exam questions don’t give a table for drawing straight line graphs so ensure students are comfortable with why and how the table is being created.

After watching

Look at other exam questions to reinforce and extend their learning.

Ask your students to create their own straight line graph equations and draw corresponding tables.

Create ‘spot the error’ questions where coordinates have been incorrectly calculated.

Students could plot their own graphs using themselves and a coordinate grid on the floor, or use the IWB for students to come and plot their own points.

Next steps would be to extend questions to applied questions - looking at real life formulae, conversion graphs, identifying reciprocal and cubic graphs. Look at the effects of m and c in the graph y=mx + c. Substitute values into formulae that need rearranging to find the unknown value.

Curriculum Notes

Suitable for teaching maths at GCSE in England, Wales and Northern Ireland and National 4/5 or Higher in Scotland.

More from The Maths Show

Exam Techniques for GCSE Maths
Ratio and Proportion
Fractions, Decimals and Percentages
Algebra and Negative Numbers