← 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 210 · 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. 1.754 − 331 =
  2. 2.543 − 366 =
  3. 3.934 − 772 =
  4. 4.158 + 383 =
  5. 5.498 + 445 =
  6. 6.603 + 371 =
  7. 7.365 + 423 =
  8. 8.285 + 466 =
  9. 9.138 + 227 =
  10. 10.568 + 604 =
  11. 11.849 − 435 =
  12. 12.444 − 208 =
  13. 13.228 + 409 =
  14. 14.335 + 212 =
  15. 15.762 + 258 =
  16. 16.896 − 683 =
  17. 17.308 + 239 =
  18. 18.257 + 219 =
  19. 19.525 − 391 =
  20. 20.854 − 112 =
  21. 21.825 − 376 =
  22. 22.134 + 355 =
  23. 23.133 + 458 =
  24. 24.559 − 272 =
  25. 25.499 + 577 =
  26. 26.214 + 259 =
  27. 27.306 + 232 =
  28. 28.560 − 375 =
  29. 29.417 + 511 =
  30. 30.560 + 301 =
  31. 31.778 + 321 =
  32. 32.784 − 351 =
  33. 33.968 − 638 =
  34. 34.937 − 796 =
  35. 35.442 + 361 =
  36. 36.287 + 211 =
  37. 37.554 − 153 =
  38. 38.741 − 194 =
  39. 39.485 + 197 =
  40. 40.706 − 218 =

Answer key

  1. 423
  2. 177
  3. 162
  4. 541
  5. 943
  6. 974
  7. 788
  8. 751
  9. 365
  10. 1172
  11. 414
  12. 236
  13. 637
  14. 547
  15. 1020
  16. 213
  17. 547
  18. 476
  19. 134
  20. 742
  21. 449
  22. 489
  23. 591
  24. 287
  25. 1076
  26. 473
  27. 538
  28. 185
  29. 928
  30. 861
  31. 1099
  32. 433
  33. 330
  34. 141
  35. 803
  36. 498
  37. 401
  38. 547
  39. 682
  40. 488

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