How to teach your child to read a graph
Teach your child to read a column graph by checking its title, labels and scale, then finding and comparing values in an original pet-vote example.
Your child can count in twos and compare small numbers.
Teach your child to read a graph by checking what it shows before answering a question. Read the title, identify the labels and work out the scale. Then trace the relevant column to its value. This gives them a reason for an answer beyond "that bar looks taller".
Begin with a small column graph containing a few categories. Keep the numbers manageable so your conversation can focus on reading the information.
Understand the idea
A column graph uses columns to show quantities. The horizontal axis can name categories, such as different pets. The vertical axis shows values, such as the number of votes for each pet.
The scale tells us how numbers increase along that vertical axis. A gap between marks might represent one, two, five or another amount. Count the labelled values before counting the gaps.
Say: "What is this graph about? What does each column stand for? How many votes does each step up represent?"
The answers should come from the graph. If there is a legend or key, read that too. It explains symbols or colours when they represent different information.
See it worked through
A scale that counts in twos
Our original graph is titled Favourite pets. Its categories are cats, dogs and fish. The vertical axis is labelled Votes and marked 0, 2, 4, 6, 8, 10, 12.
The cats column reaches 8 votes, dogs reaches 12 votes, and fish reaches 4 votes.
Ask: "How many more votes did dogs receive than cats?"
Read both values before calculating. Dogs received 12 and cats received eight. The difference is 12 − 8 = 4 votes.
The dogs column is two marked intervals higher than the cats column. Each interval represents two votes, so those two intervals also show a difference of four votes.
Ask your child to point to the category label and then trace across from the column's top to the number axis. This makes it easier to see whether a wrong answer came from reading the value or from the later calculation.
Try it together
Read and compare the votes
Use the same graph to answer two questions:
- How many votes are shown altogether?
- How many more votes did dogs receive than fish?
Ask your child to say which values they need before they calculate. Then invite them to invent a question about the graph for you to answer.
Check the answer
The total is 8 + 12 + 4 = 24 votes. Dogs received 12 − 4 = 8 more votes than fish.
The first question combines all three categories. The second compares two categories, so adding their values would answer a different question.
Check their understanding
Ask: "Could we tell which pet is most popular in every Australian school from this graph?" No. This example only shows its own set of 24 votes. It does not describe every school.
Then ask what happens if you redraw the same vote counts with a scale increasing by fours instead of twos. The columns cross fewer marked intervals, but the vote counts stay eight, 12 and four. Their values come from the labels and scale together.
Make it easier or harder
Make it easier by drawing the same data with an axis marked in ones. Write each value above its column at first, then remove those extra labels once your child can read the axis.
Make it harder by asking which categories together have as many votes as dogs. Cats and fish make 8 + 4 = 12. You can also collect a small household vote, record the counts and let your child choose a scale for a new graph.
Teaching notes
NSW Education's numeracy teaching advice identifies axes, labels, scales, legends and titles as features to teach explicitly. The invented pet-vote data here offers a simple way to practise reading those features.
Numeracy practice
Help your child apply their maths understanding with practice questions and explanations.
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