← 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 428 · 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. 1.862 − 654 =
  2. 2.366 + 468 =
  3. 3.552 − 424 =
  4. 4.644 + 457 =
  5. 5.211 + 135 =
  6. 6.193 + 359 =
  7. 7.324 + 398 =
  8. 8.305 + 625 =
  9. 9.221 + 207 =
  10. 10.248 + 397 =
  11. 11.957 − 115 =
  12. 12.625 − 197 =
  13. 13.569 + 121 =
  14. 14.557 − 165 =
  15. 15.777 + 234 =
  16. 16.823 − 521 =
  17. 17.669 − 277 =
  18. 18.649 + 505 =
  19. 19.887 − 187 =
  20. 20.132 + 602 =
  21. 21.233 + 629 =
  22. 22.468 + 382 =
  23. 23.484 − 378 =
  24. 24.810 − 213 =
  25. 25.795 − 608 =
  26. 26.553 + 681 =
  27. 27.267 + 231 =
  28. 28.252 + 588 =
  29. 29.127 + 387 =
  30. 30.941 − 282 =
  31. 31.785 + 322 =
  32. 32.144 + 658 =
  33. 33.656 − 507 =
  34. 34.283 + 168 =
  35. 35.562 − 434 =
  36. 36.129 + 524 =
  37. 37.439 − 158 =
  38. 38.813 − 605 =
  39. 39.607 − 159 =
  40. 40.256 + 532 =

Answer key

  1. 208
  2. 834
  3. 128
  4. 1101
  5. 346
  6. 552
  7. 722
  8. 930
  9. 428
  10. 645
  11. 842
  12. 428
  13. 690
  14. 392
  15. 1011
  16. 302
  17. 392
  18. 1154
  19. 700
  20. 734
  21. 862
  22. 850
  23. 106
  24. 597
  25. 187
  26. 1234
  27. 498
  28. 840
  29. 514
  30. 659
  31. 1107
  32. 802
  33. 149
  34. 451
  35. 128
  36. 653
  37. 281
  38. 208
  39. 448
  40. 788

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