• How to use a word formula.
  • How to use a formula given with letters.
  • What is the correct order to apply the steps of a formula.
  • How to work backwards from a formula to a starting value.
  • How to work out a formula using multiple values.


The cost of taking a school group of x adults and y children on a trip to a museum can be worked out using the formula below:

Cost (in £s) = 90 + 5x + 2y

What is the total cost of taking a group of 18 adults and 65 children to the museum?

Show Answer


The ‘Guide to the QTS Numeracy Skills Test’ book contains a full chapter on formulae, including step-by-step explanations and demonstrations of all the skills that you need to know, and a practice exercise on the topic with 20 questions.

If you would like to be sent fully worked solutions to that exercise, just pop your details in the boxes and we will send them over to you.

If you are still struggling with this topic, we have created a selection of resources to provide all the help you need.


  • QTS Numeracy Revision Book – The Guide to the QTS Skills Tests book devotes a whole chapter to the topic of formulae, with detailed methods, worked examples and plenty of practice questions for you to have a go at.
  • Practice QTS Numeracy Tests – Want to put your skills to the test and see how ready you are? Take a look at our selection of practice papers for the QTS numeracy test.
  • QTS Numeracy Revision Cheat Sheets – Our cheat sheets boil down everything you need to know to just the key points on the topic. They are a perfect resource for your last minute revision!
  • QTS Numeracy Coaching – Coaching is the ultimate in personalised support. Book your one-on-one Skype video calls where you can work through the issues that you struggle with at a pace that suits you.