← 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 181 · 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. 1.179 + 121 =
  2. 2.694 + 376 =
  3. 3.421 − 144 =
  4. 4.538 + 178 =
  5. 5.124 + 305 =
  6. 6.339 + 176 =
  7. 7.822 − 148 =
  8. 8.955 − 487 =
  9. 9.422 − 226 =
  10. 10.706 + 587 =
  11. 11.473 + 663 =
  12. 12.363 + 175 =
  13. 13.490 − 331 =
  14. 14.935 − 213 =
  15. 15.688 − 321 =
  16. 16.710 + 417 =
  17. 17.443 + 352 =
  18. 18.740 − 625 =
  19. 19.676 + 485 =
  20. 20.283 + 571 =
  21. 21.459 + 671 =
  22. 22.702 − 371 =
  23. 23.785 + 472 =
  24. 24.513 − 231 =
  25. 25.572 − 347 =
  26. 26.324 + 268 =
  27. 27.554 − 427 =
  28. 28.429 + 161 =
  29. 29.425 − 118 =
  30. 30.178 + 605 =
  31. 31.259 + 121 =
  32. 32.622 − 149 =
  33. 33.286 + 284 =
  34. 34.646 + 581 =
  35. 35.503 + 415 =
  36. 36.483 + 336 =
  37. 37.793 − 191 =
  38. 38.470 − 113 =
  39. 39.773 + 311 =
  40. 40.750 − 255 =

Answer key

  1. 300
  2. 1070
  3. 277
  4. 716
  5. 429
  6. 515
  7. 674
  8. 468
  9. 196
  10. 1293
  11. 1136
  12. 538
  13. 159
  14. 722
  15. 367
  16. 1127
  17. 795
  18. 115
  19. 1161
  20. 854
  21. 1130
  22. 331
  23. 1257
  24. 282
  25. 225
  26. 592
  27. 127
  28. 590
  29. 307
  30. 783
  31. 380
  32. 473
  33. 570
  34. 1227
  35. 918
  36. 819
  37. 602
  38. 357
  39. 1084
  40. 495

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