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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 547 · 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. 1.883 − 172 =
  2. 2.629 + 246 =
  3. 3.190 + 519 =
  4. 4.137 + 116 =
  5. 5.528 − 351 =
  6. 6.533 − 416 =
  7. 7.690 + 189 =
  8. 8.766 + 306 =
  9. 9.665 + 386 =
  10. 10.755 − 382 =
  11. 11.748 + 134 =
  12. 12.617 + 129 =
  13. 13.133 + 576 =
  14. 14.310 + 358 =
  15. 15.957 − 227 =
  16. 16.477 + 353 =
  17. 17.518 − 221 =
  18. 18.267 + 312 =
  19. 19.142 + 636 =
  20. 20.467 + 188 =
  21. 21.278 + 517 =
  22. 22.382 + 544 =
  23. 23.939 − 255 =
  24. 24.481 + 605 =
  25. 25.602 + 281 =
  26. 26.218 + 439 =
  27. 27.621 − 423 =
  28. 28.182 + 342 =
  29. 29.183 + 483 =
  30. 30.760 − 366 =
  31. 31.962 − 832 =
  32. 32.417 + 638 =
  33. 33.419 + 264 =
  34. 34.420 + 667 =
  35. 35.580 − 216 =
  36. 36.762 + 355 =
  37. 37.527 + 627 =
  38. 38.742 + 534 =
  39. 39.744 − 291 =
  40. 40.707 − 335 =

Answer key

  1. 711
  2. 875
  3. 709
  4. 253
  5. 177
  6. 117
  7. 879
  8. 1072
  9. 1051
  10. 373
  11. 882
  12. 746
  13. 709
  14. 668
  15. 730
  16. 830
  17. 297
  18. 579
  19. 778
  20. 655
  21. 795
  22. 926
  23. 684
  24. 1086
  25. 883
  26. 657
  27. 198
  28. 524
  29. 666
  30. 394
  31. 130
  32. 1055
  33. 683
  34. 1087
  35. 364
  36. 1117
  37. 1154
  38. 1276
  39. 453
  40. 372

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