CCSS.Math.Content.2.MD.B.6

Math2nd GradeRelate addition and subtraction to length.

The standard

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 for Mathematics · Measurement and Data

What this standard means

Students need to use a number line as a measurement tool. They start at 0, read equal spaces, and show whole numbers as lengths. They also show addition and subtraction by making jumps forward or backward, staying within 100.

Mastery means students can draw or use a number line with equal spacing, label it correctly, and explain each jump in a sum or difference. Common trouble spots are uneven spaces, starting jumps from the wrong number, counting tick marks instead of intervals, and mixing up forward and backward jumps.

Ways to teach it

  • Hands-on activity: Give students tape number lines on desks and counters to model 27 + 15 with jumps of 10 and 5.
  • Discussion prompt: Ask, “How is 34 to 46 on a number line like measuring a length?” and have partners explain.
  • Quick assessment: Students draw a number line to solve 58 - 23, label jumps, and write one sentence explaining their work.
  • Real-world connection: Use a hallway distance map where classroom doors are marked by numbers, then ask students to find distances between rooms.

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Related standards

  • CCSS.Math.Content.7.NS.A.1

    Apply and extend previous understandings of addition and subtraction to add and subtract rational numbers; represent addition and subtraction on a horizontal or...

  • CCSS.Math.Content.3.NF.A.2

    Understand a fraction as a number on the number line; represent fractions on a number line diagram.

  • CCSS.Math.Content.3.NF.A.2b

    Represent a fraction a/b on a number line diagram by marking off a lengths 1/b from 0. Recognize that the resulting interval has size a/b and that its endpoint ...

  • CCSS.Math.Content.6.NS.C.6

    Understand a rational number as a point on the number line. Extend number line diagrams and coordinate axes familiar from previous grades to represent points on...

Standard text verified against corestandards.org on July 10, 2026.

Page updated July 10, 2026.

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