3-digit addition worksheets
Adding 3-digit numbers column by column, with regrouping in the ones and tens. This is the core written addition method children use from grade 3 on.
Download the free 3-digit addition worksheet (PDF)
3-digit addition worksheet
What’s on the worksheet
- 50 questions on 3-digit addition, sized for US Letter paper
- 2 pages of questions plus an answer key on the last page
- Written for grades 2–3, matching Common Core 2.NBT.B.7, 3.NBT.A.2
- Name and date lines at the top, and room to show the work
Sample questions from this worksheet
- 894 + 28 =
- 760 + 119 =
- 712 + 37 =
- 539 + 99 =
- 515 + 317 =
- 400 + 298 =
Preview the worksheet and answer key
Make a new 3-digit addition worksheet
Need another page for extra practice, a retake or a second group in class? The free Mathify Kids test maker builds a fresh 3-digit addition worksheet with different numbers every time. Choose Core, Standard or Challenge level, print it with its own answer key, or let your child take it on screen and see the score straight away.
3-digit addition: a worked example (358 + 267)
358 + 267 ───── 625
- Ones: 8 + 7 = 15. Write 5, carry 1 ten.
- Tens: 5 + 6 + 1 = 12. Write 2, carry 1 hundred.
- Hundreds: 3 + 2 + 1 = 6. The answer is 625.
How to use it at home and in class
At home
Before adding, ask your child to estimate: 358 + 267 is about 400 + 300 = 700, so 625 is reasonable. Ten problems a day works better than a whole sheet at once. Mark them together with the answer key, then ask your child to explain one they got wrong: finding the mistake themselves is where the learning happens.
In class
Use the first row as a warm-up, a full page for independent practice, or five questions as an exit ticket. For a retake or a second group, make a new version with the test maker so every child gets different numbers.
Mistakes to watch for
- Starting from the hundreds instead of the ones.
- Carrying in one column but not the next when both need it.
What to practice before and after 3-digit addition
- Before: 2-digit addition. If this sheet is a struggle, go back a step.
- After: subtraction facts, once this one is mostly right.
- Learn it first: the 3-digit addition lesson and the addition chart.
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Questions parents ask
What does regrouping mean in 3-digit addition?
When a column adds to 10 or more, 10 ones become 1 ten, or 10 tens become 1 hundred, and that 1 moves to the next column.
What grade is this 3-digit addition worksheet for?
It is written for grades 2–3 and matches Common Core standards 2.NBT.B.7, 3.NBT.A.2.
Can I get a different version of this 3-digit addition worksheet?
Yes. Use the free Mathify Kids test maker to make a new 3-digit addition worksheet with different numbers every time, at Core, Standard or Challenge level, with its own answer key.