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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 669 · 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. 1.567 + 201 =
  2. 2.290 + 464 =
  3. 3.519 − 379 =
  4. 4.548 − 194 =
  5. 5.604 − 157 =
  6. 6.806 − 118 =
  7. 7.363 + 527 =
  8. 8.644 − 355 =
  9. 9.435 + 262 =
  10. 10.848 − 492 =
  11. 11.639 − 319 =
  12. 12.228 + 348 =
  13. 13.135 + 195 =
  14. 14.946 − 411 =
  15. 15.266 + 473 =
  16. 16.580 + 465 =
  17. 17.607 + 164 =
  18. 18.213 + 542 =
  19. 19.329 + 384 =
  20. 20.825 − 221 =
  21. 21.562 − 306 =
  22. 22.698 − 535 =
  23. 23.448 + 437 =
  24. 24.663 + 538 =
  25. 25.718 + 177 =
  26. 26.534 + 232 =
  27. 27.552 − 271 =
  28. 28.182 + 273 =
  29. 29.619 − 321 =
  30. 30.861 − 474 =
  31. 31.946 − 652 =
  32. 32.513 − 231 =
  33. 33.575 + 477 =
  34. 34.424 + 211 =
  35. 35.383 + 205 =
  36. 36.434 + 641 =
  37. 37.448 + 384 =
  38. 38.357 + 142 =
  39. 39.758 + 453 =
  40. 40.488 − 114 =

Answer key

  1. 768
  2. 754
  3. 140
  4. 354
  5. 447
  6. 688
  7. 890
  8. 289
  9. 697
  10. 356
  11. 320
  12. 576
  13. 330
  14. 535
  15. 739
  16. 1045
  17. 771
  18. 755
  19. 713
  20. 604
  21. 256
  22. 163
  23. 885
  24. 1201
  25. 895
  26. 766
  27. 281
  28. 455
  29. 298
  30. 387
  31. 294
  32. 282
  33. 1052
  34. 635
  35. 588
  36. 1075
  37. 832
  38. 499
  39. 1211
  40. 374

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