Measuring things and making a line plot
In 2nd grade, children learn to measure several objects to the nearest whole unit and to show the measurements on a line plot.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
Try these with your child
These are real questions from our 2nd grade practice. Tap the speaker to hear one read aloud, or the light bulb for a hint, and talk about the answer together.
Question 1 of 3
Sarah measured the length of her crayons. She found lengths of 5 inches, 6 inches, 5 inches, 7 inches, and 6 inches. How many crayons were 5 inches long?
- 2
- 5
- 1
Why this matters
Line plots let your child see at a glance what a set of measurements is saying: which value came up most and how spread out the results are. They bring measuring, number lines, and data together. In 3rd grade, line plots use measurements to the nearest half and quarter inch, and in 4th and 5th grade children solve problems with line plots that show fractions. Science class uses the same skill.
Where kids can get stuck
- Spacing the numbers unevenly, or leaving out a number nobody measured, such as skipping 8 when no object was 8 inches.
- Drawing the Xs in different sizes or spacing, so the stacks are hard to compare.
- Rounding inconsistently, recording a pencil a little over 5 inches as 6 inches instead of 5.
How you can help
- Measure everyone's shoe or hand in the family to the nearest inch or centimeter, then draw a simple line plot on paper and add an X for each person.
- Measure the length of several leaves, sticks, or crayons to the nearest inch, and plot them together. Ask which length appeared most often.
- Measure the same table three times with a ruler and record each result, then talk about why the measurements might be slightly different.
Want a little more? Watch the kid-friendly video below together, or try Bobby's Math Club for free practice that adapts to your child.
Kid-friendly explanation
Questions parents ask
Why is my child learning to make line plots?
Line plots show a set of measurements clearly, so your child can see which lengths are most common and how spread out they are. They combine measuring, number lines, and data. This builds skills for reading graphs and understanding information, which grow in importance in later grades.
What is the difference between a line plot and a bar graph?
A line plot uses a number line and places an X above a number each time that value appears, which works well for measurements like lengths. A bar graph uses bars to show how many are in each category, such as favorite colors. Your child will make both in 2nd grade.
What does measure to the nearest whole unit mean?
It means choosing the whole number that the length is closest to. If a crayon is a little more than 3 inches long, but not halfway to 4, it is about 3 inches to the nearest inch. In 3rd grade, children measure more precisely, to the nearest half inch and quarter inch.
Make learning math fun
Bobby's Math Club turns 2nd grade math practice into something fun to do together.
- Free, unlimited practice for every child in your family
- Questions matched to your child’s level, a few minutes a day
- Hints when they are stuck, and a celebration when it clicks
Written by Robert “Bobby” Barnett
Bobby is an award-winning math teacher, the author of Meet Every Learner’s Needs, and the father of two elementary-school math learners. He uses Bobby’s Math Club with his own kids a few times every week. Learn more or contact Bobby.
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Join the clubNote for teachers: This skill is covered by Common Core math standard 2.MD.D.9: “Generate measurement data by measuring lengths of several objects to the nearest whole unit, or by making repeated measurements of the same object. Show the measurements by making a line plot, where the horizontal scale is marked off in whole-number units.” Learn how Bobby's Math Club can help your students grow. (Common Core 2.MD.9)