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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 994 · 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. 1.127 + 161 =
  2. 2.518 − 324 =
  3. 3.531 − 247 =
  4. 4.559 − 457 =
  5. 5.354 + 355 =
  6. 6.482 + 131 =
  7. 7.782 − 427 =
  8. 8.237 + 296 =
  9. 9.470 − 221 =
  10. 10.695 − 288 =
  11. 11.260 + 155 =
  12. 12.439 − 167 =
  13. 13.878 − 601 =
  14. 14.914 − 253 =
  15. 15.420 + 471 =
  16. 16.262 + 297 =
  17. 17.529 − 182 =
  18. 18.540 + 506 =
  19. 19.648 − 355 =
  20. 20.782 − 676 =
  21. 21.589 + 529 =
  22. 22.633 − 435 =
  23. 23.503 − 386 =
  24. 24.596 − 169 =
  25. 25.140 + 523 =
  26. 26.444 − 343 =
  27. 27.842 − 646 =
  28. 28.977 − 234 =
  29. 29.135 + 301 =
  30. 30.446 − 207 =
  31. 31.247 + 556 =
  32. 32.872 − 224 =
  33. 33.149 + 625 =
  34. 34.941 − 768 =
  35. 35.686 + 666 =
  36. 36.468 + 119 =
  37. 37.268 + 142 =
  38. 38.932 − 604 =
  39. 39.607 + 374 =
  40. 40.220 + 446 =

Answer key

  1. 288
  2. 194
  3. 284
  4. 102
  5. 709
  6. 613
  7. 355
  8. 533
  9. 249
  10. 407
  11. 415
  12. 272
  13. 277
  14. 661
  15. 891
  16. 559
  17. 347
  18. 1046
  19. 293
  20. 106
  21. 1118
  22. 198
  23. 117
  24. 427
  25. 663
  26. 101
  27. 196
  28. 743
  29. 436
  30. 239
  31. 803
  32. 648
  33. 774
  34. 173
  35. 1352
  36. 587
  37. 410
  38. 328
  39. 981
  40. 666

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