Reading and comparing bar and line graphs
Solve comparison, sum, and difference problems using information presented in a bar graph
What a learner can do afterwards
- Read a line graph of temperature over a week and identify the warmest day
- Find the difference in rainfall between two months from a line graph
- Explain what a rising/falling line means on a time-series graph
1 · Read
A bar graph uses bars to compare groups. The taller the bar, the bigger the number. Now you will use bar graphs to solve problems: finding the biggest or smallest group, adding two bars together, and working out how many more one bar shows than another.
To find how many more one bar shows than another, read both numbers and subtract the smaller one from the bigger one. A graph shows 11 children walked to school and 6 came by car. 11 minus 6 is 5, so 5 more children walked than came by car.
To find a total, add the bars. A graph shows 4 children chose mystery books and 9 chose adventure books. 4 plus 9 is 13, so 13 children chose those two kinds of book altogether.
Read the question carefully. Altogether or total means add the bars. How many more or how many fewer means subtract the smaller number from the bigger one.
Read each bar's number first. Then add the bars for a total, or subtract the smaller number from the bigger one to compare them.
More to read
Reading bar graphs
Bar graphs turn tables into towers. The title tells the topic, labels name each bar, and the scale sets the values. Taller bars mean bigger numbers.
Read across from the top of a bar to the scale. Halfway lines count too, so estimate carefully.
Reading bar graphs: multi-step
Harder graphs ask multi-step questions. Start by reading each value, then combine them: add bars together or subtract to find gaps. Jot values down as you read.
Plan before calculating. Knowing whether you need a total or a difference saves muddled maths.
Key ideas: Interpret line graphs
Line graphs join points to show change over time. A rising line means growth, a falling line means a drop, and a flat line means nothing changed. Steepness shows speed.
Read the labels on both axes first. Time usually runs along the bottom while the measured thing climbs the side.
Creating bar graphs
To build a bar graph, give every category its own bar with gaps between. Choose a scale that fits your biggest value, then draw each bar to its height and label everything.
Neat scales make honest graphs. Equal steps keep every bar truthful.
Explore more
2 · Watch
Take it off screen
Where it sits
Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
17 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.