← 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 496 · 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. 1.429 + 636 =
  2. 2.568 − 155 =
  3. 3.602 − 375 =
  4. 4.730 − 395 =
  5. 5.606 + 351 =
  6. 6.520 − 264 =
  7. 7.741 + 253 =
  8. 8.692 − 378 =
  9. 9.513 − 241 =
  10. 10.418 − 218 =
  11. 11.440 + 581 =
  12. 12.979 − 659 =
  13. 13.164 + 661 =
  14. 14.483 − 371 =
  15. 15.309 + 572 =
  16. 16.316 + 194 =
  17. 17.671 − 242 =
  18. 18.383 + 315 =
  19. 19.505 + 513 =
  20. 20.468 + 347 =
  21. 21.823 − 361 =
  22. 22.402 + 492 =
  23. 23.138 + 546 =
  24. 24.549 − 161 =
  25. 25.221 + 228 =
  26. 26.742 − 511 =
  27. 27.292 + 457 =
  28. 28.681 + 215 =
  29. 29.692 − 375 =
  30. 30.877 − 456 =
  31. 31.313 + 441 =
  32. 32.780 + 541 =
  33. 33.330 + 181 =
  34. 34.484 + 464 =
  35. 35.622 + 363 =
  36. 36.497 − 121 =
  37. 37.589 − 239 =
  38. 38.140 + 134 =
  39. 39.661 + 258 =
  40. 40.208 + 484 =

Answer key

  1. 1065
  2. 413
  3. 227
  4. 335
  5. 957
  6. 256
  7. 994
  8. 314
  9. 272
  10. 200
  11. 1021
  12. 320
  13. 825
  14. 112
  15. 881
  16. 510
  17. 429
  18. 698
  19. 1018
  20. 815
  21. 462
  22. 894
  23. 684
  24. 388
  25. 449
  26. 231
  27. 749
  28. 896
  29. 317
  30. 421
  31. 754
  32. 1321
  33. 511
  34. 948
  35. 985
  36. 376
  37. 350
  38. 274
  39. 919
  40. 692

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