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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 282 · 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. 1.822 − 181 =
  2. 2.607 + 225 =
  3. 3.139 + 171 =
  4. 4.593 + 396 =
  5. 5.582 − 415 =
  6. 6.639 − 112 =
  7. 7.418 − 121 =
  8. 8.838 − 305 =
  9. 9.331 + 681 =
  10. 10.818 − 293 =
  11. 11.191 + 451 =
  12. 12.445 + 457 =
  13. 13.344 + 253 =
  14. 14.639 − 458 =
  15. 15.458 − 337 =
  16. 16.508 + 352 =
  17. 17.309 + 151 =
  18. 18.960 − 276 =
  19. 19.611 + 505 =
  20. 20.255 + 551 =
  21. 21.773 + 248 =
  22. 22.879 − 161 =
  23. 23.775 − 116 =
  24. 24.537 + 136 =
  25. 25.171 + 237 =
  26. 26.154 + 275 =
  27. 27.821 − 245 =
  28. 28.554 + 218 =
  29. 29.540 − 281 =
  30. 30.256 + 652 =
  31. 31.711 − 578 =
  32. 32.611 − 381 =
  33. 33.728 + 574 =
  34. 34.967 − 332 =
  35. 35.653 − 185 =
  36. 36.665 − 135 =
  37. 37.491 − 306 =
  38. 38.666 − 169 =
  39. 39.500 + 616 =
  40. 40.746 − 609 =

Answer key

  1. 641
  2. 832
  3. 310
  4. 989
  5. 167
  6. 527
  7. 297
  8. 533
  9. 1012
  10. 525
  11. 642
  12. 902
  13. 597
  14. 181
  15. 121
  16. 860
  17. 460
  18. 684
  19. 1116
  20. 806
  21. 1021
  22. 718
  23. 659
  24. 673
  25. 408
  26. 429
  27. 576
  28. 772
  29. 259
  30. 908
  31. 133
  32. 230
  33. 1302
  34. 635
  35. 468
  36. 530
  37. 185
  38. 497
  39. 1116
  40. 137

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