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Grade 3 adding within 1000 worksheets

3.NBT.A.2 Number and operations

Printable adding within 1000 worksheets for grade 3, aligned to Common Core standard 3.NBT.A.2. Three-digit addition.

Make a worksheet on this skill

Free, instant, no signup. Choose 5–40 problems, three difficulty levels, and a printable answer key.

Sample problems

  1. 398 + 208 = 606
  2. 148 + 297 = 445
  3. 206 + 118 = 324
  4. 406 + 34 = 440
  5. 409 + 56 = 465
  6. 127 + 199 = 326
  7. 127 + 108 = 235
  8. 169 + 321 = 490

These eight are one sample at medium difficulty — the generator makes a different set every time.

A worked example

398 + 208 = 606

  1. Add the hundreds: 300 + 200 = 500
  2. Add the ones: 8 + 8 = 16
  3. Put the parts together: 500 + 90 + 16 = 606

Every problem on the answer key can show its steps like this — turn on “Show steps” before downloading.

About these worksheets

Number work rewards repetition with different numbers rather than the same sheet twice. Every sheet is generated fresh, so you can print a new one on the same skill as often as you need — different numbers, same difficulty.

Pick how many problems you want and whether they should be easy, medium or hard, then download a PDF with a matching answer key. The key can show the worked steps for every problem, which is what a parent needs to see where a wrong answer went wrong.

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All 19 grade 3 skills