Math worksheet
Three-Digit Addition Worksheets
Column addition with hundreds, tens, and ones, mixing problems that carry with ones that do not.
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- Grade
- Grade 3
- Ages
- 8–9
- Problems per page
- 16
- Format
- Stacked in columns
- Answer key
- Included
- Paper
- US Letter or A4
About this worksheet
Three-digit addition uses the same steps as two-digit addition, applied one more time: add the ones, carry if needed, add the tens, carry if needed, then add the hundreds. The sheet mixes problems that carry once, twice, or not at all, so children have to check each column rather than assume.
Estimation is a useful check here. Rounding 358 + 274 to 400 + 300 shows the answer should be near 700, so an answer like 532 is a clear sign a carry was missed.
- 01
Answer key included
Every sheet ends with a matching answer key page, so checking work takes seconds.
- 02
New problems in one click
Open the sheet in the editor and generate a fresh set with the same settings whenever you need another page.
- 03
Sized for young writers
Large digits with room to write each answer, on US Letter or A4 paper.
Questions
- Do these problems include regrouping?
- Some do and some do not, which is deliberate: children practice deciding in each column whether to carry.
- What grade is three-digit addition?
- It is usually taught in second and third grade, after two-digit addition with regrouping.
- Are these three-digit addition worksheets free?
- Yes. The sample sheet on this page, with its answer key, is a free PDF in US Letter or A4, no account needed. Generating and previewing new problems is free too; printing and downloading custom sheets come with Pro, which also removes the preview watermark.