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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 471 · 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. 1.647 − 328 =
  2. 2.461 − 256 =
  3. 3.501 − 362 =
  4. 4.650 − 325 =
  5. 5.598 + 588 =
  6. 6.795 − 645 =
  7. 7.717 − 252 =
  8. 8.387 + 581 =
  9. 9.659 + 345 =
  10. 10.500 − 238 =
  11. 11.826 − 716 =
  12. 12.429 − 318 =
  13. 13.625 + 656 =
  14. 14.419 − 157 =
  15. 15.874 − 247 =
  16. 16.757 + 197 =
  17. 17.388 + 511 =
  18. 18.310 + 513 =
  19. 19.477 + 225 =
  20. 20.960 − 514 =
  21. 21.266 + 441 =
  22. 22.495 − 191 =
  23. 23.742 − 364 =
  24. 24.348 + 337 =
  25. 25.590 + 168 =
  26. 26.625 − 121 =
  27. 27.579 + 151 =
  28. 28.579 − 318 =
  29. 29.631 + 226 =
  30. 30.837 − 422 =
  31. 31.281 + 338 =
  32. 32.986 − 206 =
  33. 33.667 + 292 =
  34. 34.550 − 398 =
  35. 35.258 + 309 =
  36. 36.455 + 117 =
  37. 37.980 − 612 =
  38. 38.603 − 162 =
  39. 39.428 − 232 =
  40. 40.408 + 672 =

Answer key

  1. 319
  2. 205
  3. 139
  4. 325
  5. 1186
  6. 150
  7. 465
  8. 968
  9. 1004
  10. 262
  11. 110
  12. 111
  13. 1281
  14. 262
  15. 627
  16. 954
  17. 899
  18. 823
  19. 702
  20. 446
  21. 707
  22. 304
  23. 378
  24. 685
  25. 758
  26. 504
  27. 730
  28. 261
  29. 857
  30. 415
  31. 619
  32. 780
  33. 959
  34. 152
  35. 567
  36. 572
  37. 368
  38. 441
  39. 196
  40. 1080

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