← 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 934 · 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. 1.219 + 475 =
  2. 2.209 + 599 =
  3. 3.271 + 244 =
  4. 4.128 + 171 =
  5. 5.516 + 181 =
  6. 6.562 + 536 =
  7. 7.501 + 254 =
  8. 8.211 + 385 =
  9. 9.641 + 573 =
  10. 10.557 + 154 =
  11. 11.576 + 556 =
  12. 12.420 − 165 =
  13. 13.377 + 242 =
  14. 14.498 − 233 =
  15. 15.903 − 451 =
  16. 16.704 − 208 =
  17. 17.986 − 298 =
  18. 18.416 − 199 =
  19. 19.586 + 231 =
  20. 20.692 + 169 =
  21. 21.733 + 196 =
  22. 22.618 + 135 =
  23. 23.882 − 331 =
  24. 24.538 − 386 =
  25. 25.454 + 256 =
  26. 26.542 + 657 =
  27. 27.542 − 403 =
  28. 28.842 − 735 =
  29. 29.469 + 543 =
  30. 30.928 − 164 =
  31. 31.939 − 322 =
  32. 32.788 − 398 =
  33. 33.667 + 248 =
  34. 34.466 + 198 =
  35. 35.457 − 139 =
  36. 36.499 + 162 =
  37. 37.663 − 547 =
  38. 38.267 + 448 =
  39. 39.451 + 298 =
  40. 40.168 + 684 =

Answer key

  1. 694
  2. 808
  3. 515
  4. 299
  5. 697
  6. 1098
  7. 755
  8. 596
  9. 1214
  10. 711
  11. 1132
  12. 255
  13. 619
  14. 265
  15. 452
  16. 496
  17. 688
  18. 217
  19. 817
  20. 861
  21. 929
  22. 753
  23. 551
  24. 152
  25. 710
  26. 1199
  27. 139
  28. 107
  29. 1012
  30. 764
  31. 617
  32. 390
  33. 915
  34. 664
  35. 318
  36. 661
  37. 116
  38. 715
  39. 749
  40. 852

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