Measurement Line Plots
Make a line plot to display measurement data in fractions of a unit (1/2, 1/4, 1/8); solve problems involving addition and subtraction of fractions using line plot data
What a learner can do afterwards
- Create a line plot of seed growth measurements in 1/8-inch increments
- Use a line plot to find the difference between the longest and shortest specimens
- Calculate the total length of all items in a line plot by adding the fractional measurements
The lesson
A line plot shows measurements lined up above a number line. Each X stands for one measurement at that exact spot. When you measure things like seeds or leaves, the lengths often fall between whole units, so line plots use fractions such as 1/2, 1/4, or 1/8.
Mia measured 8 seedlings in eighths of an inch: 2/8, 3/8, 3/8, 5/8, 6/8, 6/8, 6/8, 7/8. Her line plot shows the tallest at 7/8 inch and the shortest at 2/8 inch. To find the difference, she subtracts: 7/8 minus 2/8 equals 5/8 inch.
Mia also wants the total length of the three seedlings that measured 6/8 inch. She adds 6/8 + 6/8 + 6/8 and gets 18/8, which is the same as 2 and 2/8 inches.
Before you add or subtract fractions from a line plot, check that the bottom numbers match. If they are already eighths, just add or subtract the top numbers and keep the 8.
A line plot lines up every measurement so you can subtract for the difference and add for the total, always keeping the denominator the same.
Watch it
Where it sits
This opens up
Where this leads
8 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.