← 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 856 · 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. 1.194 + 597 =
  2. 2.162 + 433 =
  3. 3.440 − 167 =
  4. 4.776 − 311 =
  5. 5.680 + 212 =
  6. 6.494 − 252 =
  7. 7.505 + 129 =
  8. 8.362 + 612 =
  9. 9.901 − 592 =
  10. 10.338 + 488 =
  11. 11.363 + 167 =
  12. 12.749 + 364 =
  13. 13.285 + 571 =
  14. 14.220 + 444 =
  15. 15.203 + 431 =
  16. 16.543 − 248 =
  17. 17.775 − 368 =
  18. 18.707 + 675 =
  19. 19.480 + 228 =
  20. 20.444 − 128 =
  21. 21.942 − 601 =
  22. 22.432 − 185 =
  23. 23.758 + 374 =
  24. 24.688 − 261 =
  25. 25.485 − 238 =
  26. 26.729 − 561 =
  27. 27.593 + 328 =
  28. 28.205 + 199 =
  29. 29.956 − 324 =
  30. 30.949 − 495 =
  31. 31.217 + 339 =
  32. 32.176 + 537 =
  33. 33.455 − 176 =
  34. 34.623 − 496 =
  35. 35.151 + 426 =
  36. 36.786 + 219 =
  37. 37.949 − 299 =
  38. 38.308 + 679 =
  39. 39.762 + 429 =
  40. 40.420 + 489 =

Answer key

  1. 791
  2. 595
  3. 273
  4. 465
  5. 892
  6. 242
  7. 634
  8. 974
  9. 309
  10. 826
  11. 530
  12. 1113
  13. 856
  14. 664
  15. 634
  16. 295
  17. 407
  18. 1382
  19. 708
  20. 316
  21. 341
  22. 247
  23. 1132
  24. 427
  25. 247
  26. 168
  27. 921
  28. 404
  29. 632
  30. 454
  31. 556
  32. 713
  33. 279
  34. 127
  35. 577
  36. 1005
  37. 650
  38. 987
  39. 1191
  40. 909

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