Negative numbers
Temperatures, number lines and calculating with negatives
Negative numbers are numbers below zero. You meet them on thermometers, in bank balances and even in lifts that go below ground level.
Using a number line
Numbers further left on the number line are smaller. −8 is smaller than −3.
- Adding moves you right; subtracting moves you left.
- Subtracting a negative is the same as adding: 5 − (−2) = 5 + 2 = 7.
- Multiplying or dividing: same signs give a positive, different signs give a negative. −3 × −4 = 12, −12 ÷ 3 = −4.
Worked examples
Example 1. The temperature is −4 °C. It rises by 9 degrees. What is the new temperature?
Example 2. Work out −6 − 5.
Example 3. Work out −7 × 3.
Top tips and common mistakes
- The difference between −3 °C and 5 °C is 8 degrees (count the steps).
- Two minus signs side by side make a plus: 4 − (−6) = 10.
- A bank balance of −£20 means you owe £20.
I picture a thermometer. Warmer is up, colder is down. It makes negatives easy!
Practise
Answer as many as you like. Every question is new, and you get a “correct” tick for each one you get right first time. Use “Show answer” to see a worked solution.
Quiz: earn your stamp
Printable worksheet
Negative numbers worksheet. The questions come first and the answers for grown-ups are on the last page, so you can print just the question pages.
Printing is optional. A4 size.