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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 476 · 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. 1.834 − 294 =
  2. 2.392 + 679 =
  3. 3.415 − 267 =
  4. 4.760 − 386 =
  5. 5.401 + 206 =
  6. 6.772 − 602 =
  7. 7.235 + 198 =
  8. 8.226 + 257 =
  9. 9.836 − 289 =
  10. 10.229 + 506 =
  11. 11.581 − 387 =
  12. 12.559 + 673 =
  13. 13.450 − 311 =
  14. 14.746 − 136 =
  15. 15.549 + 181 =
  16. 16.703 + 575 =
  17. 17.692 − 321 =
  18. 18.219 + 299 =
  19. 19.701 − 494 =
  20. 20.199 + 251 =
  21. 21.746 − 178 =
  22. 22.483 − 224 =
  23. 23.468 − 262 =
  24. 24.477 + 537 =
  25. 25.525 − 395 =
  26. 26.523 − 125 =
  27. 27.964 − 706 =
  28. 28.605 − 229 =
  29. 29.783 + 356 =
  30. 30.738 − 135 =
  31. 31.893 − 369 =
  32. 32.345 + 193 =
  33. 33.532 + 331 =
  34. 34.817 − 165 =
  35. 35.929 − 567 =
  36. 36.129 + 241 =
  37. 37.558 − 264 =
  38. 38.448 + 493 =
  39. 39.630 + 261 =
  40. 40.453 − 277 =

Answer key

  1. 540
  2. 1071
  3. 148
  4. 374
  5. 607
  6. 170
  7. 433
  8. 483
  9. 547
  10. 735
  11. 194
  12. 1232
  13. 139
  14. 610
  15. 730
  16. 1278
  17. 371
  18. 518
  19. 207
  20. 450
  21. 568
  22. 259
  23. 206
  24. 1014
  25. 130
  26. 398
  27. 258
  28. 376
  29. 1139
  30. 603
  31. 524
  32. 538
  33. 863
  34. 652
  35. 362
  36. 370
  37. 294
  38. 941
  39. 891
  40. 176

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