# TI-AIE: Using a number line and the expression ‘Imagine if …’: positive and negative numbers

## What this unit is about

In this unit you will explore ways to encourage your students to think about the meaning of numbers and why the concept of ‘negative numbers’ was developed.

Students first meet the minus sign when it is used to indicate the mathematical operation of subtraction; therefore, careful introduction to its use in negative numbers will be needed. Explaining that the sign is used differently and exploring why it is used for negative numbers will help your students to recognise and understand the similarities and differences in using this sign.

Through the activities in this unit you will also think about developing the use of a number line to help your students visualise the movements indicated by positive and negative numbers. Actually making those movements themselves will further help the students understand what is meant by ‘positive’ and ‘negative’. The value of saying ‘Imagine if …’ to trigger imagination when teaching mathematics is also explored.

What you can learn in this unit