← 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 537 · 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. 1.252 + 599 =
  2. 2.634 − 161 =
  3. 3.416 − 135 =
  4. 4.499 + 513 =
  5. 5.642 + 454 =
  6. 6.834 − 531 =
  7. 7.855 − 381 =
  8. 8.729 − 451 =
  9. 9.599 + 535 =
  10. 10.684 − 454 =
  11. 11.407 + 299 =
  12. 12.578 + 192 =
  13. 13.205 + 254 =
  14. 14.622 + 678 =
  15. 15.755 + 377 =
  16. 16.701 + 462 =
  17. 17.473 − 281 =
  18. 18.864 − 301 =
  19. 19.627 − 129 =
  20. 20.266 + 313 =
  21. 21.509 − 301 =
  22. 22.247 + 295 =
  23. 23.619 + 138 =
  24. 24.300 + 219 =
  25. 25.312 + 253 =
  26. 26.701 + 279 =
  27. 27.738 − 476 =
  28. 28.751 − 133 =
  29. 29.554 − 415 =
  30. 30.153 + 335 =
  31. 31.907 − 557 =
  32. 32.473 + 256 =
  33. 33.427 − 249 =
  34. 34.281 + 611 =
  35. 35.728 + 644 =
  36. 36.724 + 117 =
  37. 37.440 − 198 =
  38. 38.797 − 695 =
  39. 39.492 + 366 =
  40. 40.595 + 607 =

Answer key

  1. 851
  2. 473
  3. 281
  4. 1012
  5. 1096
  6. 303
  7. 474
  8. 278
  9. 1134
  10. 230
  11. 706
  12. 770
  13. 459
  14. 1300
  15. 1132
  16. 1163
  17. 192
  18. 563
  19. 498
  20. 579
  21. 208
  22. 542
  23. 757
  24. 519
  25. 565
  26. 980
  27. 262
  28. 618
  29. 139
  30. 488
  31. 350
  32. 729
  33. 178
  34. 892
  35. 1372
  36. 841
  37. 242
  38. 102
  39. 858
  40. 1202

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