← 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 414 · 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. 1.967 − 171 =
  2. 2.508 − 346 =
  3. 3.978 − 418 =
  4. 4.787 − 261 =
  5. 5.475 − 125 =
  6. 6.531 − 368 =
  7. 7.551 − 185 =
  8. 8.832 − 389 =
  9. 9.328 + 565 =
  10. 10.146 + 148 =
  11. 11.454 − 172 =
  12. 12.703 − 399 =
  13. 13.511 − 223 =
  14. 14.737 + 538 =
  15. 15.776 + 326 =
  16. 16.654 + 651 =
  17. 17.417 − 285 =
  18. 18.754 − 351 =
  19. 19.802 − 115 =
  20. 20.781 + 601 =
  21. 21.944 − 669 =
  22. 22.867 − 697 =
  23. 23.750 + 626 =
  24. 24.650 − 497 =
  25. 25.987 − 151 =
  26. 26.200 + 671 =
  27. 27.540 + 318 =
  28. 28.708 − 381 =
  29. 29.151 + 547 =
  30. 30.956 − 223 =
  31. 31.488 + 157 =
  32. 32.174 + 134 =
  33. 33.500 + 522 =
  34. 34.586 − 473 =
  35. 35.142 + 181 =
  36. 36.278 + 379 =
  37. 37.657 + 117 =
  38. 38.616 + 554 =
  39. 39.625 + 577 =
  40. 40.617 + 558 =

Answer key

  1. 796
  2. 162
  3. 560
  4. 526
  5. 350
  6. 163
  7. 366
  8. 443
  9. 893
  10. 294
  11. 282
  12. 304
  13. 288
  14. 1275
  15. 1102
  16. 1305
  17. 132
  18. 403
  19. 687
  20. 1382
  21. 275
  22. 170
  23. 1376
  24. 153
  25. 836
  26. 871
  27. 858
  28. 327
  29. 698
  30. 733
  31. 645
  32. 308
  33. 1022
  34. 113
  35. 323
  36. 657
  37. 774
  38. 1170
  39. 1202
  40. 1175

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