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3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 443 · 40 questions
TalentJR

How to do it in your head (Hundreds first): Keep the first number as it is and split the second into hundreds, tens and ones. Add (or take away) the hundreds first, then the tens. Finish with the ones — bridge through a ten if you need to.

NameDateTime takenScore ___ / 40
  1. 1.641 − 436 =
  2. 2.534 − 271 =
  3. 3.456 + 616 =
  4. 4.719 − 367 =
  5. 5.436 − 118 =
  6. 6.220 + 538 =
  7. 7.203 + 635 =
  8. 8.812 − 632 =
  9. 9.238 + 564 =
  10. 10.195 + 209 =
  11. 11.177 + 253 =
  12. 12.224 + 216 =
  13. 13.629 + 408 =
  14. 14.191 + 618 =
  15. 15.815 − 203 =
  16. 16.656 − 278 =
  17. 17.418 + 233 =
  18. 18.560 − 255 =
  19. 19.593 − 429 =
  20. 20.221 + 604 =
  21. 21.717 − 503 =
  22. 22.548 + 631 =
  23. 23.684 − 115 =
  24. 24.514 − 319 =
  25. 25.618 − 192 =
  26. 26.934 − 828 =
  27. 27.600 + 589 =
  28. 28.178 + 459 =
  29. 29.480 − 246 =
  30. 30.440 − 188 =
  31. 31.573 − 331 =
  32. 32.377 + 166 =
  33. 33.714 − 258 =
  34. 34.531 − 207 =
  35. 35.856 − 131 =
  36. 36.174 + 146 =
  37. 37.631 − 168 =
  38. 38.754 + 251 =
  39. 39.687 + 181 =
  40. 40.651 − 229 =

Answer key

  1. 205
  2. 263
  3. 1072
  4. 352
  5. 318
  6. 758
  7. 838
  8. 180
  9. 802
  10. 404
  11. 430
  12. 440
  13. 1037
  14. 809
  15. 612
  16. 378
  17. 651
  18. 305
  19. 164
  20. 825
  21. 214
  22. 1179
  23. 569
  24. 195
  25. 426
  26. 106
  27. 1189
  28. 637
  29. 234
  30. 252
  31. 242
  32. 543
  33. 456
  34. 324
  35. 725
  36. 320
  37. 463
  38. 1005
  39. 868
  40. 422

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