Grade 3 (age 8-9)

Bar Graph

A bar graph shows survey numbers using the length of each bar. A longer bar means a bigger number, so you can see at a glance which item has the most and the least. Like a favorite-fruit survey, class data can be tidied up with a graph and a table: the table gives exact numbers and the graph gives a quick comparison. Slide each fruit's count to watch the bars change and see the biggest one and the total in the table.

Show Data as Graphs

📊 What is a Bar Graph?

①Bar lengths represent the data values

②Compare sizes at a glance

③Longest bar = most!

Build a Bar Graph

Apple Apple8

Banana Banana5

Grape Grape12

Berry Strawberry7

Orange Tangerine3

Tabulate & Analyze

🔍 What You Can Read

①See which item is most at a glance

②Compare bar lengths for size differences

③Sum total can also be calculated

Summary

How to Draw

①X-axis (items) ②Y-axis (count) ③Draw bars

Match bar heights to the survey numbers

Reading a Graph

Taller bar = more

Bar height represents the data size

Table vs Graph

Table: exact / Graph: at a glance

Tables and graphs have different strengths

🎯 Key Points

①Bar graph shows data by bar length

②Read y-axis ticks accurately

③Longest bar = most

④Table + graph = complete data summary

⑤Always include title and axis labels

Examples and Unit Test

Example 1

In a favorite-fruit survey: apple 8, banana 5, grape 10, strawberry 7. How many students were surveyed in all?

Add the number of students for each fruit.

8 + 5 + 10 + 7 = 30 students.

▸ 30 students

The total is the sum of all the bar values on the graph.

Example 2

In the survey above, what is the difference between the most and least chosen fruit?

The most is grape with 10, the least is banana with 5.

The difference is 10 − 5 = 5.

▸ 5 students

Comparing the longest and shortest bars gives the difference.

Unit Test

On a bar graph, what does the longest bar mean?

①the least item

②the most item

③the total

④the average

▸ ② the most item

On a bar graph, a longer bar means a greater count.

So the longest bar means the item with the most.

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Finding Patterns

Big Numbers