Variables, values and relationships

The lesson finished with small group discussion with each of the picture cards where they have to record what they think are the variables, their values and any possible relationship.

Then a whole class discussion and then we try to classify these examples into proportional, inverse proportional and where there is no relationship.

It is useful to use formulations like:

If one variable goes up then the other variable also goes up

If one variable goes down then the other variable goes up or If one variable goes up then the other variable goes down.