← Add and subtract 3-digit numbers left to right lesson New set →

3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 688 · 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. 1.217 + 368 =
  2. 2.367 + 392 =
  3. 3.448 − 168 =
  4. 4.130 + 473 =
  5. 5.623 − 405 =
  6. 6.317 + 314 =
  7. 7.262 + 366 =
  8. 8.432 + 483 =
  9. 9.249 + 323 =
  10. 10.820 − 411 =
  11. 11.228 + 151 =
  12. 12.307 + 497 =
  13. 13.715 + 371 =
  14. 14.367 + 666 =
  15. 15.710 − 361 =
  16. 16.286 + 262 =
  17. 17.979 − 807 =
  18. 18.723 + 272 =
  19. 19.545 + 133 =
  20. 20.423 + 242 =
  21. 21.670 + 598 =
  22. 22.496 + 206 =
  23. 23.624 − 319 =
  24. 24.937 − 791 =
  25. 25.787 + 347 =
  26. 26.786 − 149 =
  27. 27.525 − 302 =
  28. 28.621 − 224 =
  29. 29.406 + 501 =
  30. 30.707 − 281 =
  31. 31.881 − 446 =
  32. 32.389 + 387 =
  33. 33.605 − 236 =
  34. 34.350 + 266 =
  35. 35.600 − 141 =
  36. 36.489 + 161 =
  37. 37.904 − 443 =
  38. 38.158 + 443 =
  39. 39.878 − 611 =
  40. 40.532 − 355 =

Answer key

  1. 585
  2. 759
  3. 280
  4. 603
  5. 218
  6. 631
  7. 628
  8. 915
  9. 572
  10. 409
  11. 379
  12. 804
  13. 1086
  14. 1033
  15. 349
  16. 548
  17. 172
  18. 995
  19. 678
  20. 665
  21. 1268
  22. 702
  23. 305
  24. 146
  25. 1134
  26. 637
  27. 223
  28. 397
  29. 907
  30. 426
  31. 435
  32. 776
  33. 369
  34. 616
  35. 459
  36. 650
  37. 461
  38. 601
  39. 267
  40. 177

Free mental maths lessons, practice and worksheets at talentjr.in/mental-maths