← 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 959 · 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. 1.139 + 553 =
  2. 2.417 − 208 =
  3. 3.698 − 351 =
  4. 4.443 + 633 =
  5. 5.228 + 423 =
  6. 6.254 + 203 =
  7. 7.778 + 505 =
  8. 8.299 + 211 =
  9. 9.202 + 112 =
  10. 10.648 − 349 =
  11. 11.538 − 413 =
  12. 12.453 − 273 =
  13. 13.304 + 299 =
  14. 14.376 + 568 =
  15. 15.724 − 153 =
  16. 16.157 + 486 =
  17. 17.738 + 623 =
  18. 18.428 + 368 =
  19. 19.145 + 305 =
  20. 20.501 − 271 =
  21. 21.863 − 578 =
  22. 22.267 + 188 =
  23. 23.583 − 413 =
  24. 24.278 + 623 =
  25. 25.430 + 641 =
  26. 26.435 + 469 =
  27. 27.620 + 541 =
  28. 28.196 + 391 =
  29. 29.419 − 227 =
  30. 30.195 + 545 =
  31. 31.976 − 299 =
  32. 32.126 + 255 =
  33. 33.516 − 385 =
  34. 34.450 − 245 =
  35. 35.291 + 224 =
  36. 36.624 − 426 =
  37. 37.432 − 305 =
  38. 38.846 − 648 =
  39. 39.667 − 311 =
  40. 40.417 + 192 =

Answer key

  1. 692
  2. 209
  3. 347
  4. 1076
  5. 651
  6. 457
  7. 1283
  8. 510
  9. 314
  10. 299
  11. 125
  12. 180
  13. 603
  14. 944
  15. 571
  16. 643
  17. 1361
  18. 796
  19. 450
  20. 230
  21. 285
  22. 455
  23. 170
  24. 901
  25. 1071
  26. 904
  27. 1161
  28. 587
  29. 192
  30. 740
  31. 677
  32. 381
  33. 131
  34. 205
  35. 515
  36. 198
  37. 127
  38. 198
  39. 356
  40. 609

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