Go Math! Grade 2, Chapter 9: Length in Metric Units
In this unit, your child measures length in centimeters and meters, the metric units. They use centimeter rulers and meter sticks, estimate lengths, and find how much longer one object is than another. They also solve story problems about length. It mirrors the inches and feet work from before, and next the measurements turn into data and graphs.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
What is my child learning in Chapter 9?
- Measuring in centimeters with a ruler and in meters with a meter stick, lining up the zero mark. Learn more: Measuring with a ruler, yardstick, or tape
- Measuring an object in centimeters and in meters and explaining why the meter count is smaller. Learn more: Measuring in inches and in centimeters
- Estimating lengths in centimeters and meters, using a fingertip for about 1 centimeter and a big step for about 1 meter. Learn more: Estimating lengths in inches, feet, and meters
- Measuring two objects in centimeters and subtracting to find how much longer one is. Learn more: Measuring how much longer one thing is
- Solving story problems about lengths in centimeters and meters and labeling each answer. Learn more: Story problems about length
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 about 1 centimeter to estimate the length of a crayon or a spoon, then check with a ruler and compare.
- Take giant steps of about a meter across a room or hallway and count them, then measure with a tape to compare.
- Measure two pencils in centimeters and ask how much longer one is. Then ask how long they would be end to end.
Where kids can get stuck
- Thinking a centimeter is longer than an inch, so estimates in centimeters come out much too small.
- Giving the longer pencil's length instead of how much longer it is than the shorter one.
- Mixing up the inch side and the centimeter side of a ruler, so one measurement uses the wrong unit.
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.
- metric
- The measuring system that uses centimeters and meters.
- estimate
- A smart guess about an amount or a length, made before measuring or counting.
- length
- How long something is from one end to the other.
- compare
- To decide which is more, less, longer, or shorter, and by how much.
- difference
- The answer when you subtract; it also tells how much more one amount is.
Ready to build your child’s confidence with centimeters and meters?
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 Go Math! Grade 2 Chapter 9 cover?
Go Math! Grade 2 Chapter 9 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.
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.