Temperatures below and above zero
A temperature can rise from a negative number to a positive number.
Moving to the right means the temperature is increasing.
Year 6
Use negative numbers in context, and calculate intervals across zero
Interpret negative numbers in real contexts and work out intervals that pass through zero.
Lesson overview
Number - number and place value
Negative numbers are useful for temperatures, heights below sea level, money owed and floors below ground. When we calculate an interval across zero, we count the distance from the negative value up to zero and then on to the positive value.
Calculate an interval across zero
The interval from -3 to 4 is 7 because it is 3 to reach zero and 4 more to reach 4.
| Part of interval | Size |
|---|---|
| -3 to 0 | 3 |
| 0 to 4 | 4 |
| Total interval | 7 |
Split the journey at zero when it helps you see the distance clearly.
Use a context
A lift can move from floor -2 up to floor 5.
Below ground is shown with negative numbers.
Worked example
A diver moves from -6 metres to 2 metres. What is the interval?
| Section | Distance |
|---|---|
| -6 to 0 | 6 |
| 0 to 2 | 2 |
- Start at -6 metres.
- Count from -6 up to 0. That interval is 6.
- Then count from 0 up to 2. That interval is 2.
- Add 6 and 2, so the total interval is 8 metres.
Try it
Keep the order on the number line clear and split the interval at zero if needed.
Question 1
Which temperature is lower?
Question 2
What is the interval from -4 to 3?
| Part | Distance |
|---|---|
| -4 to 0 | 4 |
| 0 to 3 | 3 |
Question 3
A lift moves from floor -1 to floor 6. What interval does it travel?
Question 4
Which statement is correct?
Question 5
A temperature rises from -8 degrees to -1 degree. How much does it rise?
Common mistakes
Watch for these when working through the lesson.
- Treating -2 as greater than -5 because 2 is smaller than 5.
- Forgetting to count the distance from the negative number up to zero.
- Mixing up the direction of movement in a real context.
Related topics
These ideas fit closely with this lesson.
- Read, write, order and compare numbers up to 10,000,000 and determine the value of each digit.
- Solve number and practical problems that involve place value.
- Use estimation to check answers and decide an appropriate degree of accuracy.