← 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 197 · 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. 1.164 + 491 =
  2. 2.551 + 248 =
  3. 3.888 − 355 =
  4. 4.705 + 238 =
  5. 5.134 + 355 =
  6. 6.311 + 261 =
  7. 7.493 − 193 =
  8. 8.474 − 311 =
  9. 9.389 + 153 =
  10. 10.400 + 661 =
  11. 11.670 − 146 =
  12. 12.157 + 468 =
  13. 13.697 + 128 =
  14. 14.342 + 535 =
  15. 15.630 + 582 =
  16. 16.442 − 168 =
  17. 17.932 − 565 =
  18. 18.450 − 147 =
  19. 19.283 + 395 =
  20. 20.872 − 147 =
  21. 21.472 − 165 =
  22. 22.369 + 293 =
  23. 23.515 − 113 =
  24. 24.253 + 571 =
  25. 25.539 + 566 =
  26. 26.260 + 492 =
  27. 27.329 + 196 =
  28. 28.683 + 357 =
  29. 29.547 + 476 =
  30. 30.125 + 548 =
  31. 31.844 − 417 =
  32. 32.723 − 394 =
  33. 33.260 + 202 =
  34. 34.284 + 342 =
  35. 35.817 − 454 =
  36. 36.707 − 337 =
  37. 37.486 − 297 =
  38. 38.892 − 237 =
  39. 39.493 − 296 =
  40. 40.211 + 645 =

Answer key

  1. 655
  2. 799
  3. 533
  4. 943
  5. 489
  6. 572
  7. 300
  8. 163
  9. 542
  10. 1061
  11. 524
  12. 625
  13. 825
  14. 877
  15. 1212
  16. 274
  17. 367
  18. 303
  19. 678
  20. 725
  21. 307
  22. 662
  23. 402
  24. 824
  25. 1105
  26. 752
  27. 525
  28. 1040
  29. 1023
  30. 673
  31. 427
  32. 329
  33. 462
  34. 626
  35. 363
  36. 370
  37. 189
  38. 655
  39. 197
  40. 856

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