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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 624 · 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. 1.560 − 316 =
  2. 2.594 − 191 =
  3. 3.819 − 498 =
  4. 4.976 − 846 =
  5. 5.711 + 396 =
  6. 6.183 + 387 =
  7. 7.495 + 216 =
  8. 8.553 + 555 =
  9. 9.434 − 119 =
  10. 10.659 + 671 =
  11. 11.558 − 382 =
  12. 12.271 + 441 =
  13. 13.837 − 117 =
  14. 14.289 + 121 =
  15. 15.479 − 171 =
  16. 16.618 − 338 =
  17. 17.513 + 321 =
  18. 18.962 − 793 =
  19. 19.923 − 484 =
  20. 20.632 − 206 =
  21. 21.168 + 538 =
  22. 22.671 − 421 =
  23. 23.411 + 367 =
  24. 24.942 − 506 =
  25. 25.948 − 465 =
  26. 26.695 + 512 =
  27. 27.266 + 145 =
  28. 28.213 + 572 =
  29. 29.831 − 489 =
  30. 30.435 − 148 =
  31. 31.764 + 602 =
  32. 32.487 − 185 =
  33. 33.722 − 211 =
  34. 34.810 − 243 =
  35. 35.198 + 216 =
  36. 36.789 − 688 =
  37. 37.734 − 163 =
  38. 38.247 + 327 =
  39. 39.597 + 328 =
  40. 40.641 − 124 =

Answer key

  1. 244
  2. 403
  3. 321
  4. 130
  5. 1107
  6. 570
  7. 711
  8. 1108
  9. 315
  10. 1330
  11. 176
  12. 712
  13. 720
  14. 410
  15. 308
  16. 280
  17. 834
  18. 169
  19. 439
  20. 426
  21. 706
  22. 250
  23. 778
  24. 436
  25. 483
  26. 1207
  27. 411
  28. 785
  29. 342
  30. 287
  31. 1366
  32. 302
  33. 511
  34. 567
  35. 414
  36. 101
  37. 571
  38. 574
  39. 925
  40. 517

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