← 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 172 · 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. 1.221 + 458 =
  2. 2.604 − 114 =
  3. 3.729 + 545 =
  4. 4.706 + 591 =
  5. 5.319 + 277 =
  6. 6.674 − 214 =
  7. 7.567 − 197 =
  8. 8.609 − 331 =
  9. 9.671 − 375 =
  10. 10.715 + 321 =
  11. 11.511 + 267 =
  12. 12.966 − 162 =
  13. 13.938 − 583 =
  14. 14.730 + 163 =
  15. 15.825 − 579 =
  16. 16.782 − 293 =
  17. 17.443 + 509 =
  18. 18.509 − 205 =
  19. 19.755 + 275 =
  20. 20.494 − 171 =
  21. 21.684 − 197 =
  22. 22.163 + 436 =
  23. 23.562 − 207 =
  24. 24.677 + 581 =
  25. 25.234 + 431 =
  26. 26.459 − 359 =
  27. 27.557 + 155 =
  28. 28.295 + 463 =
  29. 29.496 + 128 =
  30. 30.547 + 459 =
  31. 31.608 + 537 =
  32. 32.447 − 291 =
  33. 33.438 + 426 =
  34. 34.558 + 521 =
  35. 35.208 + 537 =
  36. 36.705 + 347 =
  37. 37.602 − 295 =
  38. 38.443 + 187 =
  39. 39.612 + 459 =
  40. 40.422 + 436 =

Answer key

  1. 679
  2. 490
  3. 1274
  4. 1297
  5. 596
  6. 460
  7. 370
  8. 278
  9. 296
  10. 1036
  11. 778
  12. 804
  13. 355
  14. 893
  15. 246
  16. 489
  17. 952
  18. 304
  19. 1030
  20. 323
  21. 487
  22. 599
  23. 355
  24. 1258
  25. 665
  26. 100
  27. 712
  28. 758
  29. 624
  30. 1006
  31. 1145
  32. 156
  33. 864
  34. 1079
  35. 745
  36. 1052
  37. 307
  38. 630
  39. 1071
  40. 858

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