3-Digit Addition Worksheets

2nd-3rd gradeMathFree PDF + answer key

These 3-digit addition worksheets extend regrouping skills into the hundreds place, giving 2nd and 3rd graders practice adding three-digit numbers with one or more carries. Each printable PDF pairs with an answer key so parents and teachers can check work quickly.

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How to teach 3-digit column addition with regrouping

  1. 1

    Work one column at a time

    Cover the tens and hundreds columns with a sticky note so your child focuses only on the ones column until it's solved and any carry is recorded.

  2. 2

    Track multiple carries clearly

    When both the ones and tens columns need to carry, use two different small marks above each column so the carries never get mixed up.

  3. 3

    Connect to money

    Frame problems as adding dollar amounts in hundreds, tens, and ones to give the place values a real-world anchor.

  4. 4

    Double-check with front-end estimation

    Add just the hundreds digits first to get a rough estimate, then confirm the final answer lands close to that estimate.

Common mistakes kids make

  • Forgetting a second carry when both the ones and tens columns regroup — slow down and check each column separately before moving on.
  • Writing the hundreds digit in the wrong place when the sum reaches four digits — remind them a carry from hundreds becomes a new thousands digit.
  • Losing alignment on wider three-digit numbers — use graph paper or the printed grid to keep each digit in its column.
  • Mixing up which number was carried from which column — have them cross out each carry mark after using it.

Tips for parents and teachers

  • Review 2-digit regrouping thoroughly before starting 3-digit problems, since the process just repeats one more time.
  • Break longer worksheets into two shorter sessions to avoid careless fatigue errors.
  • Have kids say each step out loud, like 'nine plus four is thirteen, write three, carry one,' to reinforce the process.
  • Use real receipts or store flyers to create a fun word-problem version of the same skill.

Grade alignment

This worksheet supports Common Core standard 3.NBT.A.2, typically taught in 2nd-3rd grade. Use it for practice, homework, review or a timed check of fluency.

Frequently asked questions

When do students learn 3-digit addition?

3-digit addition with regrouping is typically taught in 2nd and 3rd grade, building on 2-digit regrouping skills.

Can a 3-digit addition problem require two carries?

Yes, when both the ones and tens columns sum to 10 or more, students carry twice in the same problem.

How do I help my child avoid losing track of carries?

Have them write every carried digit immediately above the correct column and cross it off once it's been added in.

Is this worksheet timed?

You can set the problem count to control length; shorter sets of 8-10 problems work well for timed practice.

What if a sum creates a 4-digit answer?

That's expected when adding two large 3-digit numbers, such as 900 + 200, and the extra carry becomes a new thousands digit.

What comes after 3-digit addition?

Kids typically move to 4-digit addition and then to mixed addition and subtraction word problems.