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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 568 · 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. 1.542 + 562 =
  2. 2.796 − 299 =
  3. 3.224 + 577 =
  4. 4.433 + 262 =
  5. 5.935 − 532 =
  6. 6.690 − 379 =
  7. 7.519 + 251 =
  8. 8.738 − 476 =
  9. 9.691 + 533 =
  10. 10.585 + 621 =
  11. 11.687 − 572 =
  12. 12.473 + 398 =
  13. 13.220 + 211 =
  14. 14.252 + 429 =
  15. 15.637 + 595 =
  16. 16.770 + 233 =
  17. 17.532 − 399 =
  18. 18.651 + 298 =
  19. 19.826 − 647 =
  20. 20.199 + 181 =
  21. 21.512 − 342 =
  22. 22.599 + 471 =
  23. 23.265 + 202 =
  24. 24.642 − 284 =
  25. 25.472 − 366 =
  26. 26.552 − 268 =
  27. 27.678 + 466 =
  28. 28.661 − 288 =
  29. 29.138 + 209 =
  30. 30.899 − 155 =
  31. 31.648 + 318 =
  32. 32.911 − 597 =
  33. 33.417 − 288 =
  34. 34.430 + 341 =
  35. 35.317 + 332 =
  36. 36.952 − 759 =
  37. 37.785 − 183 =
  38. 38.211 + 322 =
  39. 39.362 + 686 =
  40. 40.131 + 174 =

Answer key

  1. 1104
  2. 497
  3. 801
  4. 695
  5. 403
  6. 311
  7. 770
  8. 262
  9. 1224
  10. 1206
  11. 115
  12. 871
  13. 431
  14. 681
  15. 1232
  16. 1003
  17. 133
  18. 949
  19. 179
  20. 380
  21. 170
  22. 1070
  23. 467
  24. 358
  25. 106
  26. 284
  27. 1144
  28. 373
  29. 347
  30. 744
  31. 966
  32. 314
  33. 129
  34. 771
  35. 649
  36. 193
  37. 602
  38. 533
  39. 1048
  40. 305

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