← 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 144 · 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. 1.736 − 113 =
  2. 2.883 − 354 =
  3. 3.278 + 215 =
  4. 4.584 − 158 =
  5. 5.640 + 459 =
  6. 6.293 + 397 =
  7. 7.467 + 527 =
  8. 8.854 − 506 =
  9. 9.890 − 257 =
  10. 10.227 + 354 =
  11. 11.145 + 452 =
  12. 12.496 − 347 =
  13. 13.238 + 481 =
  14. 14.924 − 223 =
  15. 15.889 − 149 =
  16. 16.424 − 259 =
  17. 17.463 − 281 =
  18. 18.954 − 762 =
  19. 19.985 − 344 =
  20. 20.299 + 311 =
  21. 21.248 + 261 =
  22. 22.171 + 199 =
  23. 23.146 + 116 =
  24. 24.259 + 407 =
  25. 25.626 + 154 =
  26. 26.737 + 655 =
  27. 27.273 + 342 =
  28. 28.295 + 617 =
  29. 29.652 + 183 =
  30. 30.516 − 152 =
  31. 31.330 + 242 =
  32. 32.501 + 646 =
  33. 33.741 + 256 =
  34. 34.665 + 569 =
  35. 35.523 − 301 =
  36. 36.477 − 318 =
  37. 37.471 − 198 =
  38. 38.357 + 248 =
  39. 39.574 − 297 =
  40. 40.621 − 131 =

Answer key

  1. 623
  2. 529
  3. 493
  4. 426
  5. 1099
  6. 690
  7. 994
  8. 348
  9. 633
  10. 581
  11. 597
  12. 149
  13. 719
  14. 701
  15. 740
  16. 165
  17. 182
  18. 192
  19. 641
  20. 610
  21. 509
  22. 370
  23. 262
  24. 666
  25. 780
  26. 1392
  27. 615
  28. 912
  29. 835
  30. 364
  31. 572
  32. 1147
  33. 997
  34. 1234
  35. 222
  36. 159
  37. 273
  38. 605
  39. 277
  40. 490

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