← 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 152 · 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. 1.311 + 671 =
  2. 2.844 − 557 =
  3. 3.392 + 347 =
  4. 4.623 + 341 =
  5. 5.223 + 635 =
  6. 6.572 − 157 =
  7. 7.136 + 656 =
  8. 8.428 + 276 =
  9. 9.418 − 131 =
  10. 10.619 + 665 =
  11. 11.578 − 345 =
  12. 12.738 + 292 =
  13. 13.534 + 425 =
  14. 14.379 + 269 =
  15. 15.306 + 189 =
  16. 16.392 + 138 =
  17. 17.508 + 127 =
  18. 18.434 + 222 =
  19. 19.458 − 236 =
  20. 20.861 − 132 =
  21. 21.582 − 231 =
  22. 22.693 − 124 =
  23. 23.709 − 452 =
  24. 24.296 + 411 =
  25. 25.754 − 173 =
  26. 26.531 + 358 =
  27. 27.354 + 516 =
  28. 28.702 − 275 =
  29. 29.369 + 631 =
  30. 30.247 + 359 =
  31. 31.805 − 585 =
  32. 32.588 + 371 =
  33. 33.657 − 353 =
  34. 34.563 + 127 =
  35. 35.690 − 298 =
  36. 36.852 − 493 =
  37. 37.397 + 321 =
  38. 38.616 − 509 =
  39. 39.501 + 195 =
  40. 40.681 + 166 =

Answer key

  1. 982
  2. 287
  3. 739
  4. 964
  5. 858
  6. 415
  7. 792
  8. 704
  9. 287
  10. 1284
  11. 233
  12. 1030
  13. 959
  14. 648
  15. 495
  16. 530
  17. 635
  18. 656
  19. 222
  20. 729
  21. 351
  22. 569
  23. 257
  24. 707
  25. 581
  26. 889
  27. 870
  28. 427
  29. 1000
  30. 606
  31. 220
  32. 959
  33. 304
  34. 690
  35. 392
  36. 359
  37. 718
  38. 107
  39. 696
  40. 847

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