Graphs: read the story
Every graph tells a story. Learn what up, down and flat mean, linear and non-linear, and how to read off values. Read one step, play with it, then tap “I understand this”.
What does the graph tell?
A global graph shows how one thing changes as another thing changes, without exact numbers. Read it from left to right, like a sentence.
- The line goes up: the value increases.
- The line is flat: the value stays constant.
- The line goes down: the value decreases.
- The steeper the line, the faster the change.
Read the story
Choose a story and tap “Next part” to read the graph piece by piece.
The bottom axis is usually time, and time only runs forward. So from left to right the graph tells what happened first, and what came after.
From story to graph
You can also draw a graph from a story. Break the story into parts and decide for each part: does it go up, down or stay flat?
Build a graph
Choose for each part of the car trip what the speed does.
A speed graph that is flat does not mean the car is standing still! It is driving at a constant speed. Only when the line lies on 0 is it standing still.
Linear, non-linear, discrete and continuous
Two questions help you describe a graph: Is it a straight line or a curve? And is it a line that runs on, or just separate dots?
Compare the kinds
Choose a kind of graph.
A line between two dots means there are values in between. Between 2 and 3 tickets there is nothing: you cannot buy 2½ tickets. But between 2 and 3 o’clock there is time, so there we draw a line.
Read off values
If a graph has numbers on the axes, you can read off values. Go up from the bottom axis to the line, and then straight across to the left to the side axis.
The water tank
Change the minutes and read off how much water is in the tank.
Always look at the scale on each axis first. Here every square on the side axis is 20 litres, not 1.
The tap pours the same 15 ℓ in every minute. So for every step to the right the line goes up by exactly the same amount. Equal jumps make a straight line: a linear relationship.
Play: which graph fits?
Graph detective
Read the story and tap the graph that fits.
Correct: 0Check yourself
- Read from left to right: up = increases, flat = constant, down = decreases.
- Steeper line = faster change.
- Straight line = linear; curve = non-linear.
- Separate dots = discrete; a line that runs on = continuous.
Write these points in your maths book. Read them again the night before the test.
Quick questions
Tap an answer. If you get one wrong, read why and go back to that step. You get new questions every time.
You ticked all 5 steps! Now you are ready for the quiz.- Practice sheet for this classQuestions + memo · 1 A4 pagePractice sheet
- Numbers, Patterns and Algebra8 pages · PDFPaperMemo
- Patterns and algebra8 pages · PDFPaperMemo
Ready for more? The Grade 7 graphs quiz gives you new questions every time.
- One step a day is enough. Ten calm minutes work better than an hour the night before the test.
- Look at a graph in the newspaper or on the news together (temperature, petrol price) and ask: “What happened? Where did it change fastest?”
- Ask your child to tell you the rule in their own words. If they can explain it, they understand it.
- The ticks (“I understand this”) are saved on this device only. We never ask for names or emails.
Follows CAPS for Grade 7 Maths. Always check your teacher’s notes and textbook too.