Skip to main content
Common Core Math2nd GradeNumbers in Base Ten

2.NBT.6: Add Up to Four Two-Digit Numbers

Also written as 2.NBT.B.6 and CCSS.MATH.CONTENT.2.NBT.B.6 · Cluster: Use place value understanding and properties of operations to add and subtract.

Make a Four-Addend WorksheetAll 26 2nd Grade Math Standards

The Official Wording

Add up to four two-digit numbers using strategies based on place value and properties of operations.

Common Core State Standards, Grade 2, Number & Operations in Base Ten · Read it at the source · Checked October 14, 2026

What 2.NBT.6 Means in Plain English

Second graders add three or four two-digit numbers in one go, like 28 + 35 + 17 + 12, by collecting the tens, 70, and the ones, 22, then combining them: 92. Pairs that make ten, like 8 and 2, speed up the ones.

The point is the properties of operations in action: the order and grouping of addends can change without changing the sum, which is why tens can be collected first. Next comes adding within 1,000 (2.NBT.7), and in 3rd grade the same freedom to regroup applies to multiplication (3.OA.5).

2.NBT.6 I Can Statements

  • I can add up to four two-digit numbers.
  • I can group the tens together and the ones together.
  • I can check a sum by adding in a different order.

2.NBT.6 Worked Example

Four addends, sorted into tens and ones before anything is added, which is the whole trick.

Problem

Add 28 + 35 + 17 + 12.

Four addends, tens together and ones together
  1. Line up the tens: 20, 30, 10 and 10. Add them in any order.20 + 30 + 10 + 10 = 70
  2. Now the ones. Look for pairs that make ten: 8 and 2, then 5 and 7 make 12.8 + 2 = 10, 5 + 7 = 12
  3. The ones come to 22, which is 2 tens and 2 ones.10 + 12 = 22
  4. Put the tens and the ones back together.70 + 22 = 92
Answer28 + 35 + 17 + 12 = 92

Check it: Add in a different order: 28 + 12 = 40, 35 + 17 = 52, and 40 + 52 = 92. Two routes, one answer.

Common Mistakes with 2.NBT.6

Carrying the ones total as a single digit

Ones make 22, writes 2 and forgets the two tens: 72

Try this: Write the ones total, 22, on its own line, then add it to the tens total, 70 + 22, with nothing carried in the head.

Running total that drifts

28 + 35 = 63, 63 + 17 = 70, 70 + 12 = 82

Try this: Allow the running total, but have the student write each new total down before adding the next number, and check with a second order.

A tens digit sneaks into the ones

Ones: 8 + 5 + 1 + 2 = 16, pulling the 1 of 17 in as a one

Try this: Circle the ones digits in one color and the tens digits in another before adding, so each digit joins the right pile.

Where 2.NBT.6 Fits

Comes Before1.OA.3Use the order and grouping of addends to add, like 2 + 6 + 4 as 2 + 10.1.NBT.4Add within 100 with models, tens with tens and ones with ones.
Alongside2.NBT.5Add and subtract within 100 fluently.2.NBT.9Explain why a strategy works, like why the tens can be added first.
Comes Next2.NBT.7Add and subtract within 1,000 with models and drawings.3.NBT.2Fluently add and subtract within 1,000.3.OA.5Use the commutative and associative properties to multiply.

Practice 2.NBT.6

Addition Worksheet GeneratorFree ToolColumns of three and four two-digit addends. Students circle the tens and the ones in different colors before adding.Two-digitThree or four addendsAnswer key
Make a Worksheet
Word Problem GeneratorFree ToolStories with three or four amounts to combine: points from four games, cans from four classrooms, pages read over four days.Grade 2AdditionSeveral addends
Make Word Problems

Quick Check

  1. What is 24 + 31 + 15 + 20?
  2. Add 36 + 29 + 14. Which two numbers would you pair first, and why?
  3. Four classes collected cans: 18, 25, 32 and 15. How many cans in all?

2.NBT.6: Other Names

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