← 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 769 · 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. 1.750 + 641 =
  2. 2.185 + 574 =
  3. 3.368 + 579 =
  4. 4.560 + 321 =
  5. 5.239 + 161 =
  6. 6.642 − 271 =
  7. 7.901 − 569 =
  8. 8.691 − 314 =
  9. 9.722 − 523 =
  10. 10.486 + 185 =
  11. 11.517 + 436 =
  12. 12.640 − 501 =
  13. 13.415 + 124 =
  14. 14.467 + 639 =
  15. 15.495 − 236 =
  16. 16.355 + 145 =
  17. 17.310 + 124 =
  18. 18.221 + 145 =
  19. 19.326 + 291 =
  20. 20.689 + 514 =
  21. 21.436 + 146 =
  22. 22.340 + 185 =
  23. 23.526 + 395 =
  24. 24.951 − 124 =
  25. 25.146 + 524 =
  26. 26.524 − 407 =
  27. 27.655 − 388 =
  28. 28.590 + 143 =
  29. 29.462 − 164 =
  30. 30.750 − 342 =
  31. 31.783 − 192 =
  32. 32.129 + 531 =
  33. 33.933 − 262 =
  34. 34.353 + 137 =
  35. 35.945 − 213 =
  36. 36.542 + 234 =
  37. 37.570 + 142 =
  38. 38.752 + 563 =
  39. 39.223 + 669 =
  40. 40.651 − 222 =

Answer key

  1. 1391
  2. 759
  3. 947
  4. 881
  5. 400
  6. 371
  7. 332
  8. 377
  9. 199
  10. 671
  11. 953
  12. 139
  13. 539
  14. 1106
  15. 259
  16. 500
  17. 434
  18. 366
  19. 617
  20. 1203
  21. 582
  22. 525
  23. 921
  24. 827
  25. 670
  26. 117
  27. 267
  28. 733
  29. 298
  30. 408
  31. 591
  32. 660
  33. 671
  34. 490
  35. 732
  36. 776
  37. 712
  38. 1315
  39. 892
  40. 429

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