Sunday, 19 May 2013

Substitution - do you know what it is yet?


Substitution: Do you know what it is yet?


Step 1

A bit of preparation, but once done it is a resource that can be used time and time again. Each pupil needs a set of cards numbered 0 to 9. Make them big get them laminated, held together with a elastic band and stored in a cheap envelope.


Write an expression on the board such as



Emphasise that this is an expression not an equation. You may have to tell them what the difference is.

Step 3

Now tell them a = 4, using the cards show the answer. Hopefully the will all demonstrate they know the answer is 12, if not you have an opportunity to rectify any misconceptions. You can now progress depending as always upon the answers you receive, so for example you might want to put up the expression

2a – 1


You can continue with this exercise dependent upon the age and stage of the class.

Once again the same process is followed you can ask the class show me the answer. Where you go from here is up to you. You can continue with this exercise dependent upon the age and stage of the class. For example you can take this forward when introducing brackets, what is the answer to 2(x-1)? Or when you need to tackle the big problem that we all face of when many pupils become totally confused with the difference between x2 and 2x?


This is an excellent activity for an instant assessment of what they have learnt. It ensures every child participates in the class and if you are in the UK it will satisfy some of the demands of the OFSTED inspection regime.

This activity was not thought up by me. I found it in an excellent book which is full of ideas, starters and worksheets that can be photocopied. It is not as dry as the normal text books or dare I say it teacher produced worksheet. The title is ‘Activities for Teaching Numeracy’ Year 7 algebra. The whole series is excellent and I have bought numerous copies over the years for departments I have run, oftenI have paid for them out of my own money, because I believe them to be so good.