Notes on using NegNumbers.xls

This is an attempt to help students in my GCSE retake groups who have problems remembering the rules for dealing with negative numbers.

The idea is to start off with simple adding and subtracting problems emphasizing the “walk to the right/ walk to the left” approach or “you gain £5 but lose £7 type of thinking.

We then move on to mixed signs by introducing an extra simplification stage into the problem and then doing what we did before.

Then we have multiplication with mixed signs and finally a combination of addition and multiplication with mixed signs.

The key thing seems to be getting clarity about when you use “minus times minus is plus” type rules and when you don’t and also sequencing the stages.

The first two screens have Demo Modes which walk through the stages.

There are Help buttons to remind students of the rules/method but the aim is to be able to do without these eventually.

I mainly use this in whole class teaching using an interactive whiteboard but in could also be used for individual or pair work given enough machines, or for individual revision.