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Grade 4 (age 9-10)

grade 4 Line Graph

A line graph shows an amount that changes over time as points, with the points joined by straight lines. Where the line goes up the amount is increasing, where it goes down the amount is decreasing, and the steeper the line, the bigger the change in that stretch. For changes over time, like the temperature each month or your height each year, a line graph works better than a bar graph. Change the temperature for each month from March to September; the points and lines are redrawn, and each segment shows how many degrees warmer or colder it got from the month before.

What Is a Line Graph?

📈 Change at a Glance
①Put the months along the bottom and the temperature up the side, then mark a point for each month
②Joining neighboring points with straight lines shows at a glance how the temperature changed
③A line going up means the temperature rose; a line going down means it fell
④The steeper the line, the bigger the change in that month

Drawing a Temperature Graph

8°C
14°C
19°C
24°C
27°C
26°C
22°C

Reading the Graph

🔍 Reading a Line Graph
①The highest point is the warmest month, and the lowest point is the coldest month
②In the starting graph, the temperature rises 6°C from March to April, so that line is the steepest
③From July to August it drops 1°C, so the line goes down a little
④The number next to each line is the change from the month before: + means it rose and − means it fell

Summary

Line Graph
Points for an amount that changes over time, joined by lines
It shows rises and falls at a glance
Bar Graph or Line Graph
Bars: compare sizes / Lines: change over time
Choose the graph that fits what you want to know
How Steep the Line Is
Steep = big change, gentle = small change
A flat line means nothing changed in that stretch
🎯 Summary
①A line graph shows change over time
②Put time along the bottom and the amount up the side, mark the points and join them
③A line going up means increasing; going down means decreasing
④The steeper the line, the bigger the change
⑤The title, the scale and the units tell you what the graph shows

Examples and Unit Test

Example 1
On a line graph of monthly temperatures, what does the highest point mean?
1
The height of a point shows that month's temperature.
2
So the highest point is the month with the highest temperature, the warmest month.
▸ The month with the highest temperature (the warmest month)
In the starting graph, July at 27°C is the highest point.
Example 2
On a line graph, what does a line going up to the right mean?
1
A line going up means increasing; a line going down means decreasing.
2
So while the line goes up to the right, the temperature is rising.
▸ The temperature is rising
The steeper the line, the more it rose in that stretch.
Unit Test
Which graph is best for showing how something changes over time?
①Bar graph
②Line graph
③Picture graph
④Table
▸ ② Line graph
1
A bar graph is best for comparing the sizes of several things.
2
Rising and falling over time is best seen on a line graph.
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Divisors & Multiples

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