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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 944 · 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. 1.598 + 443 =
  2. 2.619 + 276 =
  3. 3.660 − 221 =
  4. 4.435 − 154 =
  5. 5.434 − 118 =
  6. 6.343 + 245 =
  7. 7.356 + 483 =
  8. 8.676 − 211 =
  9. 9.124 + 166 =
  10. 10.972 − 523 =
  11. 11.514 + 688 =
  12. 12.477 + 518 =
  13. 13.861 − 169 =
  14. 14.460 + 396 =
  15. 15.629 − 461 =
  16. 16.484 − 167 =
  17. 17.865 − 316 =
  18. 18.872 − 217 =
  19. 19.902 − 442 =
  20. 20.975 − 338 =
  21. 21.246 + 604 =
  22. 22.131 + 322 =
  23. 23.539 − 244 =
  24. 24.616 − 231 =
  25. 25.436 − 169 =
  26. 26.657 − 141 =
  27. 27.203 + 375 =
  28. 28.437 + 533 =
  29. 29.415 − 155 =
  30. 30.898 − 745 =
  31. 31.229 + 141 =
  32. 32.931 − 673 =
  33. 33.525 − 136 =
  34. 34.561 + 304 =
  35. 35.474 + 338 =
  36. 36.269 + 622 =
  37. 37.770 − 386 =
  38. 38.423 + 455 =
  39. 39.698 + 662 =
  40. 40.648 + 149 =

Answer key

  1. 1041
  2. 895
  3. 439
  4. 281
  5. 316
  6. 588
  7. 839
  8. 465
  9. 290
  10. 449
  11. 1202
  12. 995
  13. 692
  14. 856
  15. 168
  16. 317
  17. 549
  18. 655
  19. 460
  20. 637
  21. 850
  22. 453
  23. 295
  24. 385
  25. 267
  26. 516
  27. 578
  28. 970
  29. 260
  30. 153
  31. 370
  32. 258
  33. 389
  34. 865
  35. 812
  36. 891
  37. 384
  38. 878
  39. 1360
  40. 797

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