Primary 3 Bar Graphs Study Guide
Primary 3 bar graphs in four short steps, from reading a scale to finding a missing bar. Each step has a graph to tap and a question to try.
Start here
How do you read a bar graph?
Find what one space on the axis stands for, then read each bar against it.
A bar graph shows each amount as the length of a bar. The numbers along the axis are its scale. Each equal space on the axis represents the same amount, so your child first counts the spaces between two numbered lines and divides. A bar that stops between numbered lines is read by counting on from the line below.
In this chapter, your child uses this to:
- read upright and horizontal bar graphs with different scales;
- find totals from paired bars, using the legend;
- compare a complete total with a complete total;
- find a missing bar from a total or from how many fewer, then draw it;
- work out the scale when only zero is labelled.
Step 1
Reading a bar graph with a scale
Count the spaces, then divide. Between two numbered lines there may be one or more unnumbered lines. Divide the jump between the numbers by the number of spaces to find what one space stands for. Then find the numbered line just below the end of the bar and count on.
Change the scale, then tap a group
Seed packets packed by four groups
The numbered lines go 0, 10, 20, 30, with one unnumbered line between each pair. A bar ends on the unnumbered line between 20 and 30. What does it show?
Step 2
Double bar graph questions
Read the legend, then find complete totals. A paired bar graph shows two kinds side by side, and the legend tells your child which colour is which. Altogether means every day added together, so find the total of each kind first. For how many more, compare a complete total with a complete total, not one bar with another.
Books borrowed from the class library
How many more storybooks than comics were borrowed altogether?
Team A made 20 stars and 15 boats. Team C made 30 stars and 10 boats. How many more items did Team C make than Team A?
Step 3
Bar graph missing data questions
Use the information given, then draw the bar. A total is for all the bars, so it is not the missing bar: add the bars your child can see and minus that from the total. For how many fewer or more, start from the bar named. Only then draw the missing bar against the scale.
Seeds planted by three classes
The three classes planted 75 seeds altogether. How many seeds did Class 3B plant?
Three stalls sold 90 drinks altogether. Stall A sold 30 drinks and Stall B sold 25. Stall C's bar is missing. How many drinks did Stall C sell?
Step 4
Finding the scale of a bar graph from one bar
One known bar unlocks the whole scale. Some graphs label only zero. When the question gives one bar's value, count that bar's spaces and divide to find what one space stands for. Then every other bar is its number of spaces times that amount.
Tickets sold at three booths
Only zero is labelled. Booth Q sold 63 tickets.
Only zero is labelled. A bar 5 spaces long stands for 40. What does each space stand for?
Primary 3 bar graph questions, worked step by stepRead each graph and have a go on paper. Open a hint, or the working line by line, to check.
The bar graph shows the number of kites sold at a shop from Monday to Thursday. How many kites were sold on Wednesday?
- 0 to 10: 2 spaces
- 10 ÷ 2 = 5, so each space is 5 kites
- Wednesday: 30 + 5 = 35
The horizontal bar graph shows the number of stamps collected by four children. How many more stamps did Mei Ling collect than Ravi?
- 20 ÷ 4 = 5, so each space is 5 stamps
- Mei Ling: 40 + 5 + 5 + 5 = 55
- Ravi: 20 + 5 + 5 = 30
- 55 − 30 = 25
The bar graph shows the number of boys and girls in three choir groups. How many more girls than boys are there in the three groups altogether?
- 4 ÷ 2 = 2, so each space is 2 children
- Boys: 6 + 8 + 4 = 18
- Girls: 10 + 12 + 6 = 28
- 28 − 18 = 10
The bar graph shows the number of buns a bakery sold from Monday to Thursday. The bar for Thursday is missing. The bakery sold 160 buns on the four days. How many buns did it sell on Thursday?
- 20 ÷ 2 = 10, so each space is 10 buns
- Monday to Wednesday: 40 + 30 + 50 = 120
- Thursday: 160 − 120 = 40
- Draw Thursday's bar up to the line marked 40.
The bar graph shows the number of stickers three friends have. Only zero is labelled on the scale. Hui Min has 81 stickers. How many stickers do the three friends have altogether?
- Hui Min's bar is 9 spaces long.
- 81 ÷ 9 = 9, so each space is 9 stickers.
- Arif = 7 × 9 = 63 stickers.
- Jun = 6 × 9 = 54 stickers.
- Altogether = 81 + 63 + 54 = 198 stickers.
Step 5
Check yourself
Five quick graph questions. Each answer points to the bar graph practice that fits your child.
1. Numbered lines go 0, 6, 12, 18, with one unnumbered line between each pair. A bar ends on the line between 12 and 18. What does it show?
2. A bar covers 6 spaces. Each space stood for 2. The scale changes so each space stands for 5. What does the bar show now?
3. Stall A sold 15 apples and 25 pears. Stall B sold 20 apples and 30 pears. How many more pieces of fruit did Stall B sell than Stall A?
4. Four teams scored 100 points altogether. Three of the bars show 30, 20 and 15. How many points did the fourth team score?
5. Only zero is labelled. A bar 6 spaces long stands for 48. How many spaces long is a bar for 32?
How to use this guide. Let your child do the tapping in Step 1 and say the scale aloud before any bar is read: "each space is 4". When the scale changes and the bars stay still, ask why the readings changed. That one habit carries the whole chapter.
For paired bars and missing bars, ask your child what the given total belongs to before adding anything. Then have them try a worked example on paper, with a ruler to slide along from the bar to the axis, and reveal the working only to check.
More study guides
P3 Bar Graphs lessons and practice
3 lesson videos and 39 questions across three subtopics, from Basic to Challenge, each with a worked solution.
Watch and practise →