← 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 771 · 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. 1.608 + 438 =
  2. 2.601 + 469 =
  3. 3.573 + 132 =
  4. 4.311 + 511 =
  5. 5.920 − 819 =
  6. 6.664 + 331 =
  7. 7.633 − 287 =
  8. 8.372 + 271 =
  9. 9.551 − 439 =
  10. 10.668 + 308 =
  11. 11.512 − 233 =
  12. 12.772 − 666 =
  13. 13.212 + 348 =
  14. 14.741 − 635 =
  15. 15.734 − 592 =
  16. 16.803 − 235 =
  17. 17.129 + 481 =
  18. 18.545 − 141 =
  19. 19.548 + 386 =
  20. 20.516 + 411 =
  21. 21.592 + 238 =
  22. 22.659 − 555 =
  23. 23.412 − 258 =
  24. 24.788 − 175 =
  25. 25.548 + 157 =
  26. 26.885 − 226 =
  27. 27.918 − 646 =
  28. 28.842 − 408 =
  29. 29.482 + 542 =
  30. 30.745 − 305 =
  31. 31.138 + 461 =
  32. 32.660 − 196 =
  33. 33.570 + 423 =
  34. 34.302 + 534 =
  35. 35.566 − 311 =
  36. 36.666 + 248 =
  37. 37.560 + 168 =
  38. 38.594 + 302 =
  39. 39.263 + 371 =
  40. 40.186 + 639 =

Answer key

  1. 1046
  2. 1070
  3. 705
  4. 822
  5. 101
  6. 995
  7. 346
  8. 643
  9. 112
  10. 976
  11. 279
  12. 106
  13. 560
  14. 106
  15. 142
  16. 568
  17. 610
  18. 404
  19. 934
  20. 927
  21. 830
  22. 104
  23. 154
  24. 613
  25. 705
  26. 659
  27. 272
  28. 434
  29. 1024
  30. 440
  31. 599
  32. 464
  33. 993
  34. 836
  35. 255
  36. 914
  37. 728
  38. 896
  39. 634
  40. 825

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