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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 571 · 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. 1.625 − 128 =
  2. 2.570 − 218 =
  3. 3.540 − 201 =
  4. 4.626 − 497 =
  5. 5.707 + 359 =
  6. 6.410 + 622 =
  7. 7.454 − 285 =
  8. 8.560 + 203 =
  9. 9.296 + 262 =
  10. 10.537 − 166 =
  11. 11.232 + 524 =
  12. 12.146 + 337 =
  13. 13.526 − 175 =
  14. 14.428 − 146 =
  15. 15.555 + 121 =
  16. 16.732 − 369 =
  17. 17.985 − 132 =
  18. 18.799 − 218 =
  19. 19.178 + 357 =
  20. 20.328 + 647 =
  21. 21.528 + 216 =
  22. 22.412 − 274 =
  23. 23.605 + 615 =
  24. 24.713 + 194 =
  25. 25.510 + 667 =
  26. 26.157 + 152 =
  27. 27.703 − 578 =
  28. 28.864 − 465 =
  29. 29.946 − 692 =
  30. 30.744 − 392 =
  31. 31.620 + 341 =
  32. 32.718 − 142 =
  33. 33.214 + 234 =
  34. 34.777 − 476 =
  35. 35.351 + 254 =
  36. 36.312 + 598 =
  37. 37.164 + 458 =
  38. 38.940 − 118 =
  39. 39.234 + 146 =
  40. 40.785 − 188 =

Answer key

  1. 497
  2. 352
  3. 339
  4. 129
  5. 1066
  6. 1032
  7. 169
  8. 763
  9. 558
  10. 371
  11. 756
  12. 483
  13. 351
  14. 282
  15. 676
  16. 363
  17. 853
  18. 581
  19. 535
  20. 975
  21. 744
  22. 138
  23. 1220
  24. 907
  25. 1177
  26. 309
  27. 125
  28. 399
  29. 254
  30. 352
  31. 961
  32. 576
  33. 448
  34. 301
  35. 605
  36. 910
  37. 622
  38. 822
  39. 380
  40. 597

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