← 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 433 · 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. 1.441 + 395 =
  2. 2.421 − 263 =
  3. 3.326 + 667 =
  4. 4.439 + 299 =
  5. 5.726 + 162 =
  6. 6.620 + 192 =
  7. 7.747 − 537 =
  8. 8.553 + 528 =
  9. 9.634 − 508 =
  10. 10.470 − 181 =
  11. 11.675 + 316 =
  12. 12.782 + 338 =
  13. 13.958 − 497 =
  14. 14.728 − 349 =
  15. 15.715 + 225 =
  16. 16.974 − 562 =
  17. 17.598 + 125 =
  18. 18.160 + 296 =
  19. 19.174 + 335 =
  20. 20.267 + 538 =
  21. 21.237 + 497 =
  22. 22.680 − 249 =
  23. 23.529 − 395 =
  24. 24.456 − 254 =
  25. 25.478 − 224 =
  26. 26.426 − 127 =
  27. 27.424 + 207 =
  28. 28.840 − 191 =
  29. 29.728 + 123 =
  30. 30.454 + 188 =
  31. 31.599 + 566 =
  32. 32.650 − 248 =
  33. 33.764 + 206 =
  34. 34.704 − 546 =
  35. 35.612 + 656 =
  36. 36.738 − 608 =
  37. 37.455 − 323 =
  38. 38.832 − 565 =
  39. 39.352 + 611 =
  40. 40.353 + 351 =

Answer key

  1. 836
  2. 158
  3. 993
  4. 738
  5. 888
  6. 812
  7. 210
  8. 1081
  9. 126
  10. 289
  11. 991
  12. 1120
  13. 461
  14. 379
  15. 940
  16. 412
  17. 723
  18. 456
  19. 509
  20. 805
  21. 734
  22. 431
  23. 134
  24. 202
  25. 254
  26. 299
  27. 631
  28. 649
  29. 851
  30. 642
  31. 1165
  32. 402
  33. 970
  34. 158
  35. 1268
  36. 130
  37. 132
  38. 267
  39. 963
  40. 704

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