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Common Core Math1st GradeMeasurement & Data

1.MD.2: Measure Length with Same-Size Units

Also written as 1.MD.A.2 and CCSS.MATH.CONTENT.1.MD.A.2 · Cluster: Measure lengths indirectly and by iterating length units.

Make Large-Square Graph PaperAll 21 1st Grade Math Standards

The Official Wording

Express the length of an object as a whole number of length units, by laying multiple copies of a shorter object (the length unit) end to end; understand that the length measurement of an object is the number of same-size length units that span it with no gaps or overlaps. Limit to contexts where the object being measured is spanned by a whole number of length units with no gaps or overlaps.

Common Core State Standards, Grade 1, Measurement & Data · Read it at the source · Checked October 14, 2026

What 1.MD.2 Means in Plain English

First graders measure by laying copies of one small object end to end: paper clips along a book, cubes along a pencil box. The count is the length: the book is 6 paper clips long, when every clip is the same size and touches the next.

Gaps and overlaps are the whole lesson: a gap leaves length uncounted, an overlap counts some twice. Mixing big and small clips breaks the count too. In 2nd grade the units become inches and centimeters, read off a ruler instead of counted one by one (2.MD.1).

1.MD.2 I Can Statements

  • I can lay same-size objects end to end to measure.
  • I can measure without leaving gaps or overlapping my units.
  • I can tell a length as a number, like 9 cubes long.

1.MD.2 Worked Example

A pencil box measured in linking cubes, with the placement rules that make the count mean something.

Problem

Measure the long side of a pencil box with loose linking cubes. Say the length as a number of cubes.

How many cubes long is the pencil box?
  1. Lay the pencil box flat and choose the side to measure: the long side.the pencil box, long side facing you
  2. Put the first cube right at the left end of the box, lined up with the edge, not hanging off it.cube 1 lined up with the end of the box
  3. Lay each next cube so it touches the one before it, in a straight line, with no gaps and no cube on top of another.a row of cubes, every one touching the next
  4. Stop when the row reaches the other end. The last cube ends right at the edge of the box.the row ends exactly at the right end
  5. Count the cubes, touching each one once.1, 2, 3, 4, 5, 6, 7, 8, 9
AnswerThe pencil box is 9 cubes long.

Check it: Snap the 9 cubes into a train and hold it against the box. It should cover the long side from end to end, with nothing left over and nothing sticking out.

Common Mistakes with 1.MD.2

Gaps or overlaps between units

Clips spaced apart along one stretch of the book and lying on top of each other along another

Try this: Push each unit until it just touches the one before it, then run a finger along the row feeling for spaces and bumps.

Mixed units in one row

Big and small paper clips in the same line, each counted as one

Try this: Give each pair a cup with only one size of clip, then show that one book is 5 big clips but 8 small ones.

Starting away from the end

The first cube placed a finger’s width in from the edge of the box, so the count comes out short

Try this: Have the child line the first cube up with the box’s end, checking it with a fingertip, before any other cube goes down.

Where 1.MD.2 Fits

Comes BeforeK.MD.2Compare two objects directly to see which is longer.K.CC.5Count up to 20 objects in a line, the count a length becomes.
Alongside1.MD.1Order three objects by length and compare two of them through a third.
Comes Next2.MD.1Measure length with a ruler, yardstick, meter stick or measuring tape.2.MD.2Measure one object in two units and explain why the numbers differ.

Practice 1.MD.2

Graph Paper GeneratorFree ToolLarge squares are units that already touch with no gaps. Students draw lines 4, 7 and 10 squares long, then lay a crayon on the grid and count the squares it covers.Large squaresOne page
Make Graph Paper
Math Worksheet GeneratorFree Tool1st grade measurement pages with an answer key: pictured objects with a row of paper clips or cubes beneath, to count and write as a length.Grade 1MeasurementAnswer key
Make a Worksheet

Quick Check

  1. Leo measures his shoe with paper clips and leaves a space between each one. Is his count too big or too small?
  2. A book is 8 cubes long. Mia measures it again with big paper clips. Will she get 8 again?
  3. A crayon is covered exactly by 5 cubes laid end to end with no gaps. How long is the crayon?

1.MD.2: Other Names

1.MD.21.MD.A.2CCSS.MATH.CONTENT.1.MD.A.2

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.