← 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 942 · 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. 1.411 + 141 =
  2. 2.624 − 365 =
  3. 3.550 + 621 =
  4. 4.879 − 301 =
  5. 5.671 − 507 =
  6. 6.888 − 269 =
  7. 7.735 − 323 =
  8. 8.884 − 565 =
  9. 9.653 + 559 =
  10. 10.637 − 423 =
  11. 11.293 + 361 =
  12. 12.549 − 163 =
  13. 13.219 + 127 =
  14. 14.528 + 524 =
  15. 15.928 − 216 =
  16. 16.703 − 361 =
  17. 17.295 + 332 =
  18. 18.432 + 392 =
  19. 19.161 + 151 =
  20. 20.277 + 275 =
  21. 21.500 − 242 =
  22. 22.262 + 547 =
  23. 23.485 − 233 =
  24. 24.591 − 269 =
  25. 25.540 − 316 =
  26. 26.454 + 668 =
  27. 27.692 − 333 =
  28. 28.460 − 126 =
  29. 29.224 + 326 =
  30. 30.452 − 202 =
  31. 31.455 − 187 =
  32. 32.434 − 165 =
  33. 33.688 − 322 =
  34. 34.359 + 593 =
  35. 35.325 + 551 =
  36. 36.569 + 619 =
  37. 37.140 + 429 =
  38. 38.855 − 635 =
  39. 39.879 − 368 =
  40. 40.481 + 291 =

Answer key

  1. 552
  2. 259
  3. 1171
  4. 578
  5. 164
  6. 619
  7. 412
  8. 319
  9. 1212
  10. 214
  11. 654
  12. 386
  13. 346
  14. 1052
  15. 712
  16. 342
  17. 627
  18. 824
  19. 312
  20. 552
  21. 258
  22. 809
  23. 252
  24. 322
  25. 224
  26. 1122
  27. 359
  28. 334
  29. 550
  30. 250
  31. 268
  32. 269
  33. 366
  34. 952
  35. 876
  36. 1188
  37. 569
  38. 220
  39. 511
  40. 772

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