← 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 326 · 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. 1.563 − 405 =
  2. 2.424 − 194 =
  3. 3.929 − 524 =
  4. 4.871 − 396 =
  5. 5.158 + 552 =
  6. 6.961 − 211 =
  7. 7.184 + 606 =
  8. 8.202 + 481 =
  9. 9.507 − 117 =
  10. 10.241 + 675 =
  11. 11.914 − 352 =
  12. 12.166 + 339 =
  13. 13.675 + 157 =
  14. 14.723 + 522 =
  15. 15.368 + 431 =
  16. 16.877 − 214 =
  17. 17.673 + 325 =
  18. 18.671 − 473 =
  19. 19.152 + 669 =
  20. 20.549 − 425 =
  21. 21.453 − 151 =
  22. 22.455 − 324 =
  23. 23.506 − 336 =
  24. 24.453 − 142 =
  25. 25.523 − 266 =
  26. 26.439 − 121 =
  27. 27.787 + 624 =
  28. 28.764 − 161 =
  29. 29.301 + 541 =
  30. 30.648 − 188 =
  31. 31.849 − 279 =
  32. 32.751 − 361 =
  33. 33.370 + 535 =
  34. 34.649 + 175 =
  35. 35.471 + 419 =
  36. 36.436 − 294 =
  37. 37.556 + 281 =
  38. 38.774 − 305 =
  39. 39.243 + 545 =
  40. 40.705 + 517 =

Answer key

  1. 158
  2. 230
  3. 405
  4. 475
  5. 710
  6. 750
  7. 790
  8. 683
  9. 390
  10. 916
  11. 562
  12. 505
  13. 832
  14. 1245
  15. 799
  16. 663
  17. 998
  18. 198
  19. 821
  20. 124
  21. 302
  22. 131
  23. 170
  24. 311
  25. 257
  26. 318
  27. 1411
  28. 603
  29. 842
  30. 460
  31. 570
  32. 390
  33. 905
  34. 824
  35. 890
  36. 142
  37. 837
  38. 469
  39. 788
  40. 1222

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