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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 195 · 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. 1.763 − 166 =
  2. 2.539 + 641 =
  3. 3.444 − 178 =
  4. 4.450 − 114 =
  5. 5.179 + 141 =
  6. 6.289 + 379 =
  7. 7.594 + 575 =
  8. 8.744 − 288 =
  9. 9.437 − 179 =
  10. 10.587 − 473 =
  11. 11.420 + 125 =
  12. 12.298 + 176 =
  13. 13.627 + 419 =
  14. 14.539 − 377 =
  15. 15.170 + 281 =
  16. 16.692 − 126 =
  17. 17.614 + 574 =
  18. 18.935 − 199 =
  19. 19.316 + 519 =
  20. 20.134 + 251 =
  21. 21.470 + 135 =
  22. 22.229 + 451 =
  23. 23.517 + 401 =
  24. 24.570 + 654 =
  25. 25.606 − 115 =
  26. 26.128 + 291 =
  27. 27.894 − 609 =
  28. 28.538 + 671 =
  29. 29.659 − 127 =
  30. 30.302 + 184 =
  31. 31.843 − 453 =
  32. 32.510 − 161 =
  33. 33.719 + 384 =
  34. 34.524 − 177 =
  35. 35.979 − 711 =
  36. 36.592 + 381 =
  37. 37.140 + 199 =
  38. 38.300 + 645 =
  39. 39.951 − 283 =
  40. 40.280 + 313 =

Answer key

  1. 597
  2. 1180
  3. 266
  4. 336
  5. 320
  6. 668
  7. 1169
  8. 456
  9. 258
  10. 114
  11. 545
  12. 474
  13. 1046
  14. 162
  15. 451
  16. 566
  17. 1188
  18. 736
  19. 835
  20. 385
  21. 605
  22. 680
  23. 918
  24. 1224
  25. 491
  26. 419
  27. 285
  28. 1209
  29. 532
  30. 486
  31. 390
  32. 349
  33. 1103
  34. 347
  35. 268
  36. 973
  37. 339
  38. 945
  39. 668
  40. 593

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