← 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 434 · 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. 1.731 + 425 =
  2. 2.552 + 237 =
  3. 3.678 − 261 =
  4. 4.748 − 431 =
  5. 5.953 − 361 =
  6. 6.659 + 647 =
  7. 7.697 + 384 =
  8. 8.507 − 168 =
  9. 9.513 − 118 =
  10. 10.143 + 471 =
  11. 11.726 − 124 =
  12. 12.537 − 141 =
  13. 13.574 − 334 =
  14. 14.355 + 671 =
  15. 15.215 + 416 =
  16. 16.380 + 531 =
  17. 17.422 + 344 =
  18. 18.511 + 321 =
  19. 19.706 − 181 =
  20. 20.307 + 525 =
  21. 21.903 − 204 =
  22. 22.657 + 449 =
  23. 23.574 + 133 =
  24. 24.171 + 497 =
  25. 25.343 + 264 =
  26. 26.421 − 146 =
  27. 27.853 − 528 =
  28. 28.309 + 426 =
  29. 29.326 + 121 =
  30. 30.472 + 354 =
  31. 31.355 + 525 =
  32. 32.704 − 152 =
  33. 33.707 − 481 =
  34. 34.730 + 213 =
  35. 35.843 − 598 =
  36. 36.590 + 227 =
  37. 37.747 − 509 =
  38. 38.624 + 375 =
  39. 39.900 − 357 =
  40. 40.437 − 138 =

Answer key

  1. 1156
  2. 789
  3. 417
  4. 317
  5. 592
  6. 1306
  7. 1081
  8. 339
  9. 395
  10. 614
  11. 602
  12. 396
  13. 240
  14. 1026
  15. 631
  16. 911
  17. 766
  18. 832
  19. 525
  20. 832
  21. 699
  22. 1106
  23. 707
  24. 668
  25. 607
  26. 275
  27. 325
  28. 735
  29. 447
  30. 826
  31. 880
  32. 552
  33. 226
  34. 943
  35. 245
  36. 817
  37. 238
  38. 999
  39. 543
  40. 299

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