← 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 606 · 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. 1.822 − 632 =
  2. 2.141 + 406 =
  3. 3.989 − 604 =
  4. 4.672 − 399 =
  5. 5.264 + 362 =
  6. 6.638 − 125 =
  7. 7.438 − 195 =
  8. 8.515 − 384 =
  9. 9.867 − 549 =
  10. 10.574 + 344 =
  11. 11.558 + 188 =
  12. 12.472 − 198 =
  13. 13.805 − 653 =
  14. 14.422 + 289 =
  15. 15.143 + 215 =
  16. 16.502 − 305 =
  17. 17.968 − 621 =
  18. 18.510 + 435 =
  19. 19.728 + 541 =
  20. 20.237 + 221 =
  21. 21.274 + 545 =
  22. 22.952 − 599 =
  23. 23.581 − 336 =
  24. 24.657 − 518 =
  25. 25.305 + 421 =
  26. 26.707 − 351 =
  27. 27.684 − 356 =
  28. 28.550 + 239 =
  29. 29.566 + 575 =
  30. 30.578 − 225 =
  31. 31.560 + 631 =
  32. 32.271 + 301 =
  33. 33.610 + 256 =
  34. 34.436 + 506 =
  35. 35.596 + 211 =
  36. 36.484 + 282 =
  37. 37.385 + 388 =
  38. 38.731 + 429 =
  39. 39.601 − 336 =
  40. 40.952 − 816 =

Answer key

  1. 190
  2. 547
  3. 385
  4. 273
  5. 626
  6. 513
  7. 243
  8. 131
  9. 318
  10. 918
  11. 746
  12. 274
  13. 152
  14. 711
  15. 358
  16. 197
  17. 347
  18. 945
  19. 1269
  20. 458
  21. 819
  22. 353
  23. 245
  24. 139
  25. 726
  26. 356
  27. 328
  28. 789
  29. 1141
  30. 353
  31. 1191
  32. 572
  33. 866
  34. 942
  35. 807
  36. 766
  37. 773
  38. 1160
  39. 265
  40. 136

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