← 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 415 · 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. 1.274 + 657 =
  2. 2.781 + 137 =
  3. 3.577 − 387 =
  4. 4.881 − 672 =
  5. 5.769 + 414 =
  6. 6.667 − 352 =
  7. 7.236 + 551 =
  8. 8.550 − 181 =
  9. 9.214 + 291 =
  10. 10.151 + 367 =
  11. 11.252 + 162 =
  12. 12.977 − 182 =
  13. 13.880 − 513 =
  14. 14.270 + 552 =
  15. 15.714 − 461 =
  16. 16.645 − 251 =
  17. 17.176 + 341 =
  18. 18.269 + 143 =
  19. 19.427 − 312 =
  20. 20.879 − 276 =
  21. 21.743 − 229 =
  22. 22.214 + 113 =
  23. 23.506 + 601 =
  24. 24.729 − 271 =
  25. 25.265 + 599 =
  26. 26.951 − 664 =
  27. 27.155 + 572 =
  28. 28.414 − 241 =
  29. 29.509 − 196 =
  30. 30.825 − 209 =
  31. 31.454 − 308 =
  32. 32.714 + 298 =
  33. 33.759 + 678 =
  34. 34.438 − 113 =
  35. 35.330 + 527 =
  36. 36.249 + 459 =
  37. 37.181 + 184 =
  38. 38.512 + 445 =
  39. 39.464 + 304 =
  40. 40.723 − 116 =

Answer key

  1. 931
  2. 918
  3. 190
  4. 209
  5. 1183
  6. 315
  7. 787
  8. 369
  9. 505
  10. 518
  11. 414
  12. 795
  13. 367
  14. 822
  15. 253
  16. 394
  17. 517
  18. 412
  19. 115
  20. 603
  21. 514
  22. 327
  23. 1107
  24. 458
  25. 864
  26. 287
  27. 727
  28. 173
  29. 313
  30. 616
  31. 146
  32. 1012
  33. 1437
  34. 325
  35. 857
  36. 708
  37. 365
  38. 957
  39. 768
  40. 607

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