← 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 20 · 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. 1.470 − 287 =
  2. 2.609 − 456 =
  3. 3.362 + 154 =
  4. 4.318 + 689 =
  5. 5.968 − 441 =
  6. 6.596 + 185 =
  7. 7.152 + 639 =
  8. 8.875 − 243 =
  9. 9.750 + 495 =
  10. 10.555 − 429 =
  11. 11.539 − 408 =
  12. 12.128 + 187 =
  13. 13.873 − 295 =
  14. 14.575 + 192 =
  15. 15.420 − 319 =
  16. 16.149 + 133 =
  17. 17.910 − 433 =
  18. 18.332 + 336 =
  19. 19.494 + 663 =
  20. 20.544 + 132 =
  21. 21.874 − 771 =
  22. 22.431 − 138 =
  23. 23.777 + 367 =
  24. 24.302 + 251 =
  25. 25.152 + 307 =
  26. 26.483 − 379 =
  27. 27.701 − 233 =
  28. 28.218 + 212 =
  29. 29.192 + 145 =
  30. 30.126 + 129 =
  31. 31.555 + 633 =
  32. 32.761 + 174 =
  33. 33.791 − 185 =
  34. 34.719 + 178 =
  35. 35.287 + 254 =
  36. 36.919 − 276 =
  37. 37.530 + 477 =
  38. 38.529 − 361 =
  39. 39.680 − 511 =
  40. 40.413 + 657 =

Answer key

  1. 183
  2. 153
  3. 516
  4. 1007
  5. 527
  6. 781
  7. 791
  8. 632
  9. 1245
  10. 126
  11. 131
  12. 315
  13. 578
  14. 767
  15. 101
  16. 282
  17. 477
  18. 668
  19. 1157
  20. 676
  21. 103
  22. 293
  23. 1144
  24. 553
  25. 459
  26. 104
  27. 468
  28. 430
  29. 337
  30. 255
  31. 1188
  32. 935
  33. 606
  34. 897
  35. 541
  36. 643
  37. 1007
  38. 168
  39. 169
  40. 1070

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