← 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 168 · 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. 1.914 − 782 =
  2. 2.962 − 291 =
  3. 3.436 − 263 =
  4. 4.666 − 155 =
  5. 5.331 + 341 =
  6. 6.794 − 504 =
  7. 7.798 − 595 =
  8. 8.972 − 516 =
  9. 9.717 − 292 =
  10. 10.501 − 162 =
  11. 11.459 + 303 =
  12. 12.235 + 236 =
  13. 13.985 − 636 =
  14. 14.545 − 364 =
  15. 15.900 − 717 =
  16. 16.657 + 666 =
  17. 17.777 + 171 =
  18. 18.653 − 349 =
  19. 19.492 + 261 =
  20. 20.270 + 361 =
  21. 21.826 − 642 =
  22. 22.248 + 533 =
  23. 23.574 − 275 =
  24. 24.507 + 189 =
  25. 25.507 − 191 =
  26. 26.826 − 262 =
  27. 27.483 − 326 =
  28. 28.580 + 214 =
  29. 29.311 + 436 =
  30. 30.408 + 522 =
  31. 31.216 + 309 =
  32. 32.177 + 273 =
  33. 33.310 + 592 =
  34. 34.180 + 479 =
  35. 35.357 + 557 =
  36. 36.180 + 222 =
  37. 37.633 + 161 =
  38. 38.661 + 521 =
  39. 39.552 + 598 =
  40. 40.939 − 363 =

Answer key

  1. 132
  2. 671
  3. 173
  4. 511
  5. 672
  6. 290
  7. 203
  8. 456
  9. 425
  10. 339
  11. 762
  12. 471
  13. 349
  14. 181
  15. 183
  16. 1323
  17. 948
  18. 304
  19. 753
  20. 631
  21. 184
  22. 781
  23. 299
  24. 696
  25. 316
  26. 564
  27. 157
  28. 794
  29. 747
  30. 930
  31. 525
  32. 450
  33. 902
  34. 659
  35. 914
  36. 402
  37. 794
  38. 1182
  39. 1150
  40. 576

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