Primary 4 maths · Data & graphs · About 10 minutes
Read and interpret line graphs
Read the axes and scale, locate the named observations, then compare their values.
Start the interactive lesson →Open practice activity
What you will learn
- Read and interpret line graphs
Models used: number sentences, stories, diagrams.
Before you start
Follow the change over time
The labels below the graph tell us the order of the days.
The labels below the graph tell us the order of the days.
A line connects recorded observations. Its rise or fall shows change, but it does not supply missing measurements automatically.
Values recorded on four consecutive days. Monday is 4 and Tuesday is 8. The upward line shows an increase.
8 − 4 = 4
The value increases from four to eight. From Tuesday to Wednesday the line goes down. The value decreased by 2.
8 − 6 = 2
The value decreases from eight to six.
What did the picture help us see?
From Tuesday to Wednesday the line goes down. The value decreased by 2.
Worked example: A new example, together
How much did the value change from Monday to Tuesday? Give the size of the change.
Read the axes and scale, locate the named observations, then compare their values.
A line graph records values in order; a change is a difference between specified observations.
Read the scale before the values. Each marked interval represents 2.
Read the scale before the values. How much did the value change from Monday to Tuesday? Give the size of the change.
6
Each marked interval represents 2.
Read the scale before the values. Subtract the smaller requested value from the larger.
Read the scale before the values. The answer is 6.
Read the scale before the values. Check the result against the question we started with.
Adding the size of the change to the smaller count gives the larger count.
We found 6. A line graph records values in order; a change is a difference between specified observations.
Read the scale before the values.
Common mistakes to discuss
- Reading the slope as the value. A point’s value is read from the axis; the slope only shows how quickly it changed.
Check your understanding
- Read and interpret line graphs
- interpret recorded values and changes on a line graph
- check the answer against the original quantities and units
Explain your reasoning to an adult, then try a fresh question in the interactive lesson. A result from one attempt is not proof of lasting mastery.
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