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Common Core Math2nd GradeMeasurement & Data

2.MD.4: Compare Lengths by Measuring

Also written as 2.MD.A.4 and CCSS.MATH.CONTENT.2.MD.A.4 · Cluster: Measure and estimate lengths in standard units.

Make a Subtraction WorksheetAll 26 2nd Grade Math Standards

The Official Wording

Measure to determine how much longer one object is than another, expressing the length difference in terms of a standard length unit.

Common Core State Standards, Grade 2, Measurement & Data · Read it at the source · Checked October 14, 2026

What 2.MD.4 Means in Plain English

Second graders measure two objects in the same unit, then subtract to say how much longer one is: a 14-centimeter marker and a 9-centimeter crayon differ by 5 centimeters. The answer is a length, with a unit, not just “the marker is longer.”

In 1st grade students only said which was longer (1.MD.1). Now the comparison gets a number, which is the comparing-situations work of 2.OA.1 landing on a ruler. The same subtraction drives length word problems (2.MD.5), and in 3rd grade comparisons move into mass and volume (3.MD.2).

2.MD.4 I Can Statements

  • I can measure two objects using the same unit.
  • I can subtract to find how much longer one object is.
  • I can write the difference as a length with its unit.

2.MD.4 Worked Example

A marker and a crayon, measured on the same ruler, and the subtraction that turns “longer” into “5 centimeters longer.”

Problem

Measure a marker and a crayon in centimeters. How much longer is the marker than the crayon?

How much longer is the marker?
  1. Measure the first object from the 0 mark.Marker: 14 centimeters
  2. Measure the second object the same way, in the same unit.Crayon: 9 centimeters
  3. How much longer means the difference. Subtract the shorter length from the longer one.14 − 9 = 5
  4. Write the answer as a length, with the unit, not just the number.The marker is 5 centimeters longer than the crayon.
Answer5 centimeters longer

Check it: Lay the crayon on top of the marker with their left ends lined up. The part of the marker that sticks out measures 5 centimeters.

Common Mistakes with 2.MD.4

Answering “which” instead of “how much”

“The marker is longer.” with no number

Try this: Ask “Longer by how many centimeters?” and have the student lay the objects side by side to see the extra length.

Adding the two lengths

14 + 9 = 23, so the marker is 23 centimeters longer

Try this: Point out that 23 is longer than either object. Line the two up at one end and measure only the part that sticks out.

Different units for the two objects

Marker 14 centimeters, crayon 4 inches, difference 10

Try this: Insist on one unit for both measurements before subtracting, and have the student write the unit beside each number.

Where 2.MD.4 Fits

Comes Before1.MD.1Order three objects by length and say which is longer, without a number.
Alongside2.MD.1Choose the right tool and measure each object.2.OA.1Solve compare word problems within 100, like how many more.2.NBT.5Subtract within 100 fluently.
Comes Next2.MD.5Solve word problems about lengths in the same unit.2.MD.6Show a difference as a jump on a number line.

Practice 2.MD.4

Subtraction Worksheet GeneratorFree ToolDifferences within 100 with an answer key, for the subtraction step once both lengths are measured. Have students label every answer with the unit.Within 100Two digitsAnswer key
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Word Problem GeneratorFree ToolCompare stories at the 2nd grade level: how much longer, how much shorter. Read the numbers as lengths and keep one unit per problem.Grade 2SubtractionCompare
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Quick Check

  1. A ribbon is 25 inches long. A string is 18 inches long. How much longer is the ribbon?
  2. Ana’s pencil is 16 centimeters long. Ben’s pencil is 11 centimeters long. How much shorter is Ben’s pencil?
  3. A desk is 60 inches wide and a bookshelf is 36 inches wide. How much wider is the desk?

2.MD.4: Other Names

2.MD.42.MD.A.4CCSS.MATH.CONTENT.2.MD.A.4

Common Core State Standards © Copyright 2010. National Governors Association Center for Best Practices and Council of Chief State School Officers. All rights reserved. Official wording from the Common Core State Standards PDFs at corestandards.org, last checked October 14, 2026. The explanation, I can statements, example, mistakes and practice on this page are EMStudio’s own, written beside the official wording. They are not part of the standard.