Bar Graphs and Scaled Pictographs

Reading Bar Graphs#

A bar graph is a type of data display that uses rectangular bars to show and compare quantities. Bar graphs make it easy to see patterns and compare information at a glance.

Parts of a Bar Graph#

Every bar graph has these important parts:

1. Title — tells you what the graph is about
2. Horizontal axis (x-axis) — the bottom line, usually shows the categories
3. Vertical axis (y-axis) — the side line, usually shows the numbers (values)
4. Bars — the rectangular shapes that show the data; the height of each bar shows its value
5. Scale — the numbers along the axis that help you read the values
6. Labels — words that tell you what each bar or axis represents

Scaled Bar Graphs#

In Grade 3, you will work with scaled bar graphs where each line on the scale represents more than 1. For example:

• A scale that gös by 2s: 0, 2, 4, 6, 8, 10...
• A scale that gös by 5s: 0, 5, 10, 15, 20, 25...
• A scale that gös by 10s: 0, 10, 20, 30, 40, 50...

Reading a Bar Graph Step by Step#

1. Read the title to understand the topic
2. Read the axis labels to understand what is being measured
3. Identify the scale — what dös each line represent?
4. For each bar, read its height and multiply or use the scale to find the exact value
5. Answer the questions about the data

Example#

A bar graph shows favorite fruit choices in a class. Scale: each line = 2 students.

• Apple bar reaches the 5th line: 5 × 2 = 10 students like apples
• Banana bar reaches the 3rd line: 3 × 2 = 6 students like bananas
• Strawberry bar reaches the 7th line: 7 × 2 = 14 students like strawberries

The most popular fruit is strawberry. Apple is more popular than banana.

Questions You Might Be Asked About Bar Graphs#

• Which category has the most/least?
• How many more are in one category than another? (subtract)
• How many in total across categories? (add)
• Which two categories together equal another category?