3rd Grade · Measurement & Data
3.MD.B.4: Measure to the nearest 1/2 or 1/4 inch, and show it on a line plot
3.MD.B.4 is a 3rd grade Common Core math standard in Measurement & Data. Here’s what it really covers, and how you can help your students learn it.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
The standard
Generate measurement data by measuring lengths using rulers marked with halves and fourths of an inch. Show the data by making a line plot, where the horizontal scale is marked off in appropriate units—whole numbers, halves, or quarters.
In plain words
Measure to the nearest 1/2 or 1/4 inch, and show it on a line plot.
Sample questions from student practice
These questions from Bobby's Math Club are the kinds of questions your students will see. You can try answering them to see what a student might see.
Question 1 of 3
Zoe lines up one end of a spoon with 0 on her ruler. The other end is exactly halfway between the 5-inch mark and the 6-inch mark. How long is the spoon?
- 5 1/2 inches
- 6 1/2 inches
- 5 inches
Where students can get stuck
- Lining up the object with the end of the ruler instead of the 0 mark, so every measurement is a little off.
- Confusing half-inch and quarter-inch marks, reading the mark halfway between 2 and 3 as 2 1/4 instead of 2 1/2.
- Spacing the line plot unevenly or leaving out fractions with no data, which makes the plot misleading.
Effective teaching strategies
- Have students line one end of the object up with the 0 mark, not the edge of the ruler, and measure twice to see that both readings match.
- Mark halves and fourths on a large ruler drawing and ask students to name each mark, such as 2 1/4 and 2 1/2.
- Build a line plot on a number line with evenly spaced marks, including fractions that have no data, and ask what the plot shows.
Units that teach this standard
Find where 3.MD.B.4 lands in the program you teach. Each unit has a guide written for families. Unit names and order vary between editions and districts, so your school’s own materials have the exact sequence.
Bridges in Mathematics
enVision Mathematics
Everyday Mathematics
i-Ready Classroom Mathematics
Illustrative Mathematics
Math Expressions
Reveal Math
Zearn Math
Don’t see your curriculum? Contact Bobby and we’ll see if we can help!
Share it with families
Families can read Measuring to the nearest quarter inch for a plain-language look at this skill, with three questions to try together and ideas for helping at home.
Help every student practice measurement and data at home
In Bobby's Math Club, students practice at just the right level, with a hint when they need one, a clear explanation after every question, and kid-friendly videos. Unlimited practice is free for every family.
See how it works for teachers
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.