← 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 789 · 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. 1.520 − 291 =
  2. 2.165 + 166 =
  3. 3.433 − 253 =
  4. 4.438 − 306 =
  5. 5.695 − 184 =
  6. 6.584 − 383 =
  7. 7.550 + 424 =
  8. 8.337 + 552 =
  9. 9.242 + 261 =
  10. 10.285 + 366 =
  11. 11.625 + 465 =
  12. 12.365 + 545 =
  13. 13.256 + 516 =
  14. 14.447 + 119 =
  15. 15.519 − 261 =
  16. 16.513 − 362 =
  17. 17.445 − 222 =
  18. 18.567 − 217 =
  19. 19.563 − 309 =
  20. 20.634 + 176 =
  21. 21.688 + 301 =
  22. 22.609 + 402 =
  23. 23.686 + 521 =
  24. 24.520 + 576 =
  25. 25.389 + 628 =
  26. 26.274 + 447 =
  27. 27.783 + 171 =
  28. 28.884 − 498 =
  29. 29.147 + 367 =
  30. 30.841 − 613 =
  31. 31.953 − 438 =
  32. 32.586 + 476 =
  33. 33.447 + 492 =
  34. 34.334 + 515 =
  35. 35.876 − 161 =
  36. 36.236 + 264 =
  37. 37.314 + 118 =
  38. 38.451 − 201 =
  39. 39.162 + 687 =
  40. 40.978 − 701 =

Answer key

  1. 229
  2. 331
  3. 180
  4. 132
  5. 511
  6. 201
  7. 974
  8. 889
  9. 503
  10. 651
  11. 1090
  12. 910
  13. 772
  14. 566
  15. 258
  16. 151
  17. 223
  18. 350
  19. 254
  20. 810
  21. 989
  22. 1011
  23. 1207
  24. 1096
  25. 1017
  26. 721
  27. 954
  28. 386
  29. 514
  30. 228
  31. 515
  32. 1062
  33. 939
  34. 849
  35. 715
  36. 500
  37. 432
  38. 250
  39. 849
  40. 277

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