← 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 692 · 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. 1.364 + 209 =
  2. 2.211 + 203 =
  3. 3.819 − 623 =
  4. 4.714 + 325 =
  5. 5.781 − 331 =
  6. 6.507 + 222 =
  7. 7.450 + 588 =
  8. 8.775 + 654 =
  9. 9.491 − 331 =
  10. 10.395 + 332 =
  11. 11.613 − 499 =
  12. 12.576 − 277 =
  13. 13.137 + 343 =
  14. 14.784 − 272 =
  15. 15.782 + 578 =
  16. 16.697 − 133 =
  17. 17.873 − 745 =
  18. 18.551 − 283 =
  19. 19.314 + 136 =
  20. 20.587 + 521 =
  21. 21.423 − 204 =
  22. 22.523 + 222 =
  23. 23.332 + 274 =
  24. 24.827 − 537 =
  25. 25.126 + 531 =
  26. 26.269 + 416 =
  27. 27.569 + 671 =
  28. 28.772 + 467 =
  29. 29.873 − 189 =
  30. 30.710 + 682 =
  31. 31.222 + 263 =
  32. 32.855 − 166 =
  33. 33.660 + 161 =
  34. 34.569 − 237 =
  35. 35.688 − 536 =
  36. 36.511 − 193 =
  37. 37.776 + 242 =
  38. 38.826 − 392 =
  39. 39.535 + 386 =
  40. 40.206 + 441 =

Answer key

  1. 573
  2. 414
  3. 196
  4. 1039
  5. 450
  6. 729
  7. 1038
  8. 1429
  9. 160
  10. 727
  11. 114
  12. 299
  13. 480
  14. 512
  15. 1360
  16. 564
  17. 128
  18. 268
  19. 450
  20. 1108
  21. 219
  22. 745
  23. 606
  24. 290
  25. 657
  26. 685
  27. 1240
  28. 1239
  29. 684
  30. 1392
  31. 485
  32. 689
  33. 821
  34. 332
  35. 152
  36. 318
  37. 1018
  38. 434
  39. 921
  40. 647

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