← 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 465 · 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. 1.457 + 161 =
  2. 2.169 + 145 =
  3. 3.944 − 547 =
  4. 4.523 − 325 =
  5. 5.231 + 191 =
  6. 6.505 + 163 =
  7. 7.671 + 453 =
  8. 8.764 − 531 =
  9. 9.738 + 431 =
  10. 10.796 − 569 =
  11. 11.712 + 455 =
  12. 12.789 + 464 =
  13. 13.223 + 236 =
  14. 14.922 − 749 =
  15. 15.798 − 653 =
  16. 16.662 − 285 =
  17. 17.558 − 185 =
  18. 18.547 − 185 =
  19. 19.291 + 254 =
  20. 20.246 + 177 =
  21. 21.701 − 549 =
  22. 22.737 + 546 =
  23. 23.291 + 511 =
  24. 24.484 + 262 =
  25. 25.303 + 215 =
  26. 26.157 + 655 =
  27. 27.785 − 451 =
  28. 28.657 + 501 =
  29. 29.647 − 484 =
  30. 30.497 + 611 =
  31. 31.555 − 451 =
  32. 32.966 − 467 =
  33. 33.295 + 193 =
  34. 34.692 + 198 =
  35. 35.415 − 147 =
  36. 36.604 − 302 =
  37. 37.768 − 148 =
  38. 38.667 + 658 =
  39. 39.472 − 371 =
  40. 40.700 − 346 =

Answer key

  1. 618
  2. 314
  3. 397
  4. 198
  5. 422
  6. 668
  7. 1124
  8. 233
  9. 1169
  10. 227
  11. 1167
  12. 1253
  13. 459
  14. 173
  15. 145
  16. 377
  17. 373
  18. 362
  19. 545
  20. 423
  21. 152
  22. 1283
  23. 802
  24. 746
  25. 518
  26. 812
  27. 334
  28. 1158
  29. 163
  30. 1108
  31. 104
  32. 499
  33. 488
  34. 890
  35. 268
  36. 302
  37. 620
  38. 1325
  39. 101
  40. 354

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