Eureka Math Grade 2, Module 2: Addition and Subtraction of Length Units
In this unit, your child learns what a centimeter and a meter are, measures with rulers and meter sticks, and estimates lengths. They compare lengths, find how much longer one thing is, and add and subtract lengths on a number line drawn like a ruler. It uses the adding skills from the start of the year and leads into place value to 1,000.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
What is my child learning in Module 2?
- Building a centimeter ruler from same-size pieces, then measuring with real rulers and meter sticks from the zero mark. Learn more: Measuring with a ruler, yardstick, or tape
- Measuring objects with two different units and noticing that a smaller unit takes more of them. Learn more: Measuring in inches and in centimeters
- Estimating lengths in centimeters and meters with benchmarks, like a fingertip's width for about a centimeter. Learn more: Estimating lengths in inches, feet, and meters
- Comparing two lengths and finding how many centimeters longer one is than the other. Learn more: Measuring how much longer one thing is
- Solving story problems that add or subtract lengths, such as joining two ribbons, and writing the unit. Learn more: Story problems about length
- Using a number line drawn like a ruler to add and subtract lengths, starting from 0. Learn more: Adding and subtracting on a number line
Sample questions to try together
These are real questions from our 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
A door is measured using which tool?
- Ruler
- Measuring Tape
- Small paper clip
How you can help
- Use a fingertip as a centimeter and a big step as about a meter, and estimate the length of a table or a doorway together before measuring.
- Measure two toys in centimeters and ask how much longer one is. Then lay them end to end and ask for the total length.
- Draw a "ruler" number line on paper from 0 to 20, and have your child show 8 centimeters plus 7 centimeters as two jumps.
Where kids can get stuck
- Counting the tick marks instead of the spaces between them, getting one centimeter more than the real length.
- Expecting more meters than centimeters for the same object, because a meter is bigger.
- Adding the two lengths when the question asks how much longer one is.
Practice makes perfect
Bobby's Math Club has practice problems that adapt to your child’s level, each with a detailed explanation and an easy-to-follow video, so your child can build confidence in these skills one step at a time.
Words your child will hear
- centimeter
- A small metric unit of length, about the width of a fingertip.
- meter
- A metric unit of length equal to 100 centimeters, a bit longer than a yardstick.
- meter stick
- A measuring stick that is 1 meter, or 100 centimeters, long.
- length unit
- A same-size piece, like a centimeter cube, used again and again to measure length.
- estimate
- A smart guess about an amount or a length, made before measuring or counting.
- benchmark
- A length you already know that helps you estimate, like a paper clip for about an inch.
- compare
- To decide which is more, less, longer, or shorter, and by how much.
- number line
- A line with numbers in order at equal spaces, used to count, add, and subtract.
Want to help your child master length units?
In Bobby's Math Club, your child practices these skills 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.
Join the club
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.
Which math standards does Eureka Math Grade 2 Module 2 cover?
Eureka Math Grade 2 Module 2 covers these math standards. Each one links to what it means, sample questions, and teaching strategies.
- 2.MD.A.1: Measure the length of an object by selecting and using appropriate tools.
- 2.MD.A.2: Measure the length of an object twice, using length units of different lengths.
- 2.MD.A.3: Estimate lengths using units of inches, feet, centimeters, and meters.
- 2.MD.A.4: Measure to determine how much longer one object is than another.
- 2.MD.B.5: Use addition and subtraction within 100 to solve word problems involving lengths.
- 2.MD.B.6: Represent whole numbers as lengths from 0 on a number line diagram.
For teachers: Unit names and order vary between editions and districts, so your school’s own materials have the exact sequence. Learn how Bobby's Math Club can help your students grow.