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Common Core Math3rd GradeNumbers in Base Ten

3.NBT.2: Add and Subtract Within 1000

Also written as 3.NBT.A.2 and CCSS.MATH.CONTENT.3.NBT.A.2 · Cluster: Use place value understanding and properties of operations to perform multi-digit arithmetic.

Make a 3.NBT.2 WorksheetAll 25 3rd Grade Math Standards

The Official Wording

Fluently add and subtract within 1000 using strategies and algorithms based on place value, properties of operations, and/or the relationship between addition and subtraction.

Common Core State Standards, Grade 3, Number & Operations in Base Ten · Read it at the source · Checked October 14, 2026

What 3.NBT.2 Means in Plain English

Third graders add and subtract three-digit numbers like 456 + 278 or 503 − 268 without a calculator, picking a method that suits the numbers: adding by place value, counting up on an open number line, or a written method they can explain.

The standard algorithm is welcome but not required until 4th grade, when students use it with multi-digit numbers (4.NBT.4). What third graders need is the reason behind each regroup: ten ones make a ten, and ten tens make a hundred.

3.NBT.2 I Can Statements

  • I can add two three-digit numbers by place value.
  • I can subtract across a zero by counting up.
  • I can check a subtraction answer by adding.

3.NBT.2 Worked Example

The problem that trips up most third graders, a zero in the middle, solved by turning subtraction into adding up.

Problem

Find 503 − 268.

503 − 268 by counting up
  1. There is a zero in the tens place, so regrouping gets messy. Think addition instead: 268 plus what makes 503?268 + ? = 503
  2. Hop to the next ten.268 + 2 = 270
  3. Hop to the next hundred.270 + 30 = 300
  4. Hop 200 to reach 500, then 3 more to land on 503.300 + 200 + 3 = 503
  5. Add up the hops.2 + 30 + 200 + 3 = 235
Answer503 − 268 = 235

Check it: Add back: 235 + 268 = 503. And 500 − 270 is about 230, so 235 is in the right place.

Common Mistakes with 3.NBT.2

Subtracting the smaller digit

503 − 268 = 365, taking 3 from 8 and 0 from 6

Try this: Read each column top minus bottom out loud. When the top digit is smaller, regroup or switch to counting up from 268.

Writing column sums side by side

456 + 278 = 61214

Try this: Use base-ten blocks or a place-value chart so students trade ten ones for a ten instead of writing 14 in one column.

Lining up from the left

245 + 38 written with the 3 under the 2, giving 625

Try this: Line numbers up from the ones place, or write each in expanded form first: 200 + 40 + 5 and 30 + 8.

Where 3.NBT.2 Fits

Comes Before2.NBT.7Add and subtract within 1000 with models, drawings and place-value strategies.2.NBT.5Add and subtract within 100 fluently.
Alongside3.NBT.1Round to the nearest 10 or 100 to estimate first.3.OA.8Use these sums and differences in two-step word problems.
Comes Next4.NBT.4Add and subtract multi-digit numbers with the standard algorithm.

Practice 3.NBT.2

Addition Worksheet GeneratorFree ToolThree-digit addition with and without regrouping, plus an answer key. Ask for an estimate beside each problem before students start.3-digitWith regroupingAnswer key
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Subtraction Worksheet GeneratorFree ToolThree-digit subtraction, including zeros in the middle like 503 − 268. Students check each answer by adding it back.3-digitWith regroupingAnswer key
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Quick Check

  1. 456 + 278
  2. 700 − 342
  3. A school has 615 students. 278 ride the bus. How many do not?

3.NBT.2: Other Names

3.NBT.23.NBT.A.2CCSS.MATH.CONTENT.3.NBT.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.