This activity is about moving along a temperature scale, starting at a negative number, and moving to the right if the temperature rises, and to the left if it falls.

Example 

Work out the temperature as it rises or falls.

A temperature is -4°C. What will it be if it rises 5°C?

Answer

Look at this number line.

Start at -4 and move 5 units to the right.  You will get to 1.

So -4°C + 5°C = 1°C

Let's try some questions on this.