← 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 709 · 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. 1.578 + 628 =
  2. 2.629 − 254 =
  3. 3.961 − 295 =
  4. 4.160 + 229 =
  5. 5.556 − 167 =
  6. 6.515 − 383 =
  7. 7.678 − 251 =
  8. 8.502 − 377 =
  9. 9.457 + 471 =
  10. 10.456 + 404 =
  11. 11.636 − 456 =
  12. 12.562 − 171 =
  13. 13.271 + 571 =
  14. 14.229 + 226 =
  15. 15.824 − 345 =
  16. 16.336 + 669 =
  17. 17.589 + 239 =
  18. 18.637 + 541 =
  19. 19.950 − 216 =
  20. 20.376 + 368 =
  21. 21.762 + 415 =
  22. 22.574 − 233 =
  23. 23.537 − 126 =
  24. 24.271 + 253 =
  25. 25.831 − 544 =
  26. 26.532 + 382 =
  27. 27.252 + 211 =
  28. 28.474 − 281 =
  29. 29.673 − 325 =
  30. 30.767 − 421 =
  31. 31.234 + 302 =
  32. 32.609 + 682 =
  33. 33.856 − 634 =
  34. 34.770 + 121 =
  35. 35.805 − 463 =
  36. 36.675 + 502 =
  37. 37.425 + 665 =
  38. 38.458 + 126 =
  39. 39.691 − 138 =
  40. 40.707 − 189 =

Answer key

  1. 1206
  2. 375
  3. 666
  4. 389
  5. 389
  6. 132
  7. 427
  8. 125
  9. 928
  10. 860
  11. 180
  12. 391
  13. 842
  14. 455
  15. 479
  16. 1005
  17. 828
  18. 1178
  19. 734
  20. 744
  21. 1177
  22. 341
  23. 411
  24. 524
  25. 287
  26. 914
  27. 463
  28. 193
  29. 348
  30. 346
  31. 536
  32. 1291
  33. 222
  34. 891
  35. 342
  36. 1177
  37. 1090
  38. 584
  39. 553
  40. 518

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