← 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 632 · 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 − 416 =
  2. 2.982 − 772 =
  3. 3.917 − 761 =
  4. 4.618 − 313 =
  5. 5.828 − 718 =
  6. 6.487 − 169 =
  7. 7.486 − 116 =
  8. 8.406 + 361 =
  9. 9.657 + 115 =
  10. 10.268 + 343 =
  11. 11.257 + 685 =
  12. 12.419 + 197 =
  13. 13.468 − 325 =
  14. 14.670 + 187 =
  15. 15.836 − 274 =
  16. 16.616 + 384 =
  17. 17.284 + 423 =
  18. 18.519 − 141 =
  19. 19.427 − 179 =
  20. 20.931 − 328 =
  21. 21.973 − 547 =
  22. 22.619 + 484 =
  23. 23.466 − 121 =
  24. 24.503 − 267 =
  25. 25.302 + 392 =
  26. 26.538 − 199 =
  27. 27.658 + 586 =
  28. 28.538 + 359 =
  29. 29.589 + 268 =
  30. 30.143 + 341 =
  31. 31.778 − 306 =
  32. 32.256 + 487 =
  33. 33.302 + 631 =
  34. 34.743 − 418 =
  35. 35.566 − 156 =
  36. 36.161 + 162 =
  37. 37.955 − 564 =
  38. 38.617 − 303 =
  39. 39.572 − 151 =
  40. 40.215 + 257 =

Answer key

  1. 315
  2. 210
  3. 156
  4. 305
  5. 110
  6. 318
  7. 370
  8. 767
  9. 772
  10. 611
  11. 942
  12. 616
  13. 143
  14. 857
  15. 562
  16. 1000
  17. 707
  18. 378
  19. 248
  20. 603
  21. 426
  22. 1103
  23. 345
  24. 236
  25. 694
  26. 339
  27. 1244
  28. 897
  29. 857
  30. 484
  31. 472
  32. 743
  33. 933
  34. 325
  35. 410
  36. 323
  37. 391
  38. 314
  39. 421
  40. 472

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