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Common Core Math2nd GradeMeasurement & Data

2.MD.6: Add and Subtract on a Number Line

Also written as 2.MD.B.6 and CCSS.MATH.CONTENT.2.MD.B.6 · Cluster: Relate addition and subtraction to length.

Make a Number LineAll 26 2nd Grade Math Standards

The Official Wording

Represent whole numbers as lengths from 0 on a number line diagram with equally spaced points corresponding to the numbers 0, 1, 2, ..., and represent whole-number sums and differences within 100 on a number line diagram.

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

What 2.MD.6 Means in Plain English

Second graders see a number line as a ruler with no object on it: 37 is the length from 0 to the 37 mark. Adding 26 is jumping 26 more to the right, in chunks like 10, 10, 3, 3, landing on 63. Subtracting jumps left.

The number line becomes the main model for the rest of elementary math. It carries the strategies of 2.NBT.5 as visible jumps, and in 3rd grade the same line is cut between 0 and 1 to place fractions (3.NF.2) and shows elapsed time between two clock readings (3.MD.1).

2.MD.6 I Can Statements

  • I can show a number as a length from 0 on a number line.
  • I can add two numbers by jumping right on a number line.
  • I can subtract by jumping left and reading where I land.

2.MD.6 Worked Example

One sum within 100 as four jumps, each one a length the student can point to.

Problem

Show 37 + 26 on a number line and find the sum.

37 + 26 as jumps
  1. Find 37 on the line. Its distance from 0 is 37 units, and that is what the number means here.Start at 37
  2. Add 26 in friendly jumps. Jump 20 first, as two hops of 10.37 + 10 = 47, 47 + 10 = 57
  3. Jump 3 to land on the next ten.57 + 3 = 60
  4. Jump the last 3.60 + 3 = 63
  5. Add up the jumps to be sure they total 26.10 + 10 + 3 + 3 = 26
Answer37 + 26 = 63

Check it: Go backwards: start at 63 and jump 26 to the left (3, 3, 10, 10) and you land on 37 again. That is 63 − 26 = 37.

Common Mistakes with 2.MD.6

Counting marks instead of spaces

A jump of 3 that lands 2 away because the starting mark was counted as 1

Try this: Have the student say the number of each mark they land on, so a jump of 3 from 57 is 58, 59, 60.

Unequal spaces on a hand-drawn line

A line where 10 to 20 is twice as wide as 20 to 30

Try this: Give students a printed line until the equal-spacing habit sets, and ask them to check that every ten is the same width.

Starting the line at 1

A number line whose first mark is labeled 1, so every length comes out one short

Try this: Compare the line with a ruler. Both start at 0, and the number names how far from 0 the mark is.

Where 2.MD.6 Fits

Comes Before1.MD.2A length is a count of equal units laid end to end.2.MD.1Measure with a ruler, which is a number line with an object against it.
Alongside2.NBT.5Add and subtract within 100 using place value strategies, the jumps made visible.2.MD.5Solve length word problems with drawings of rulers.2.OA.1Solve addition and subtraction word problems within 100.
Comes Next3.NF.2Place fractions on a number line between 0 and 1.3.MD.1Find elapsed time, often as jumps on a number line of minutes.

Practice 2.MD.6

Number Line GeneratorFree ToolLabeled lines from 0 to 100, marked by ones or by tens, for drawing the jumps of a sum or a difference above the line.0 to 100Step 10Labeled
Make a Number Line
Addition Worksheet GeneratorFree ToolTwo-digit sums with an answer key. Have students solve each one on a number line first and write the size of every jump above its arc.Two digitsRegroupingAnswer key
Make a Worksheet

Quick Check

  1. Start at 45 on a number line and jump 30 to the right. Where do you land?
  2. Show 58 − 24 on a number line. Where do you land?
  3. On a number line, a jump from 0 to 29 and then 15 more to the right ends where?

2.MD.6: Other Names

2.MD.62.MD.B.6CCSS.MATH.CONTENT.2.MD.B.6

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.