If you need 3rd grade 3 digit addition with regrouping worksheets that you can print right now, this page builds them for you — 20 fresh problems, an answer key underneath, and no account to create first. You will see items like 135 + 437 and 248 + 119 on the printed page, with 572 and 367 waiting on the answer key so nobody has to redo the arithmetic.
‘New set of problems’ opens the generator in its own tab. There you can change the problem count and turn the answer key on or off. ‘Print or save as PDF’ opens the print dialog — choose Save as PDF in the printer list to keep the file. The sheet fits US Letter and A4, and the answer key prints on its own page.
Fluency in addition is usually described in two parts: knowing the single-digit facts by recall, and applying a written method to bigger numbers. This sheet exercises whichever of the two the number range implies — for 135 + 437 the answer 572 should come from memory, not from counting.
What separates a confident adder from a slow one is rarely the method; it is whether the number bonds underneath are automatic. Watch how long the child hesitates before writing the first digit of 367.
The problems here use three-digit numbers that carry, which keeps the arithmetic honest without turning the page into a copying exercise. 135 + 437 and 248 + 119 are typical of the range.
Written addition is worth practising in columns — which is what these 3rd grade 3 digit addition with regrouping worksheets ask for — even when a 3rd grader can do it mentally, because the column layout is what makes four-digit work manageable later. A problem such as 124 + 258 is small enough to do mentally and worth writing out anyway.
Teachers usually place 3rd grade 3 digit addition with regrouping worksheets alongside the addition strand of most US state standards for this grade, which is where the skill sits in the majority of US state frameworks.
| # | Problem | Answer | What to check |
|---|---|---|---|
| 1 | 135 + 437 = | 572 | Watch for: counting on from the wrong number |
| 2 | 248 + 119 = | 367 | Check: treating a longer number as a bigger one |
| 3 | 786 + 115 = | 901 | Look at: guessing on the near-tens |
| 4 | 124 + 258 = | 382 | Ask about: adding right to left, then reading left to right |
| 5 | 165 + 826 = | 991 | Watch for: forgetting the carried digit |
| 6 | 176 + 525 = | 701 | Check: losing the place columns |
Try 786 + 115 together before letting the child start alone. The answer to 786 + 115 is 901, and talking through how it was reached takes about a minute and saves several minutes of guessing later in the sheet.
The item 248 + 119 is worth doing slowly. The answer to 248 + 119 is 367, and the route to it is the route every other problem on this sheet takes — which is why the sheet has 20 of them rather than one.
Because the numbers are random, there is no shared answer list to look up: the key printed behind your sheet is the only one that fits it, and it shows 572 for 135 + 437.
The answer key is generated with the worksheet, not written by hand, so it always matches the sheet in front of you — 135 + 437 is listed as 572, 248 + 119 as 367, and so on down the page.
To save these 3rd grade 3 digit addition with regrouping worksheets instead of printing them, choose 'Save as PDF' in the printer list. You get the worksheet and the answer key as a single PDF, on Letter or A4 depending on your printer settings.
The sheet is laid out to fit one page on both US Letter and A4. Leave the browser scaling at 100% and turn headers and footers off, and the 20 problems land inside the margins on either paper size.
When these become easy, move along the related links below rather than adding more problems to the same sheet.
→ Free 3rd Grade Math Worksheets · → Free Addition Worksheets
Free printable math worksheets from a working math academy director in Korea. Problems come from our own code, not from a published workbook. Every sheet prints on US Letter or A4 with its answer key. All worksheets · Worksheet generator · Korean site
Last updated: 2026-09-13