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3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 610 · 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. 1.919 − 806 =
  2. 2.514 + 254 =
  3. 3.229 + 531 =
  4. 4.428 + 612 =
  5. 5.546 − 251 =
  6. 6.564 + 149 =
  7. 7.680 + 644 =
  8. 8.273 + 255 =
  9. 9.646 − 157 =
  10. 10.200 + 219 =
  11. 11.489 − 314 =
  12. 12.311 + 273 =
  13. 13.897 − 297 =
  14. 14.428 − 243 =
  15. 15.598 − 439 =
  16. 16.483 − 353 =
  17. 17.594 − 353 =
  18. 18.662 − 433 =
  19. 19.798 − 431 =
  20. 20.664 − 451 =
  21. 21.243 + 281 =
  22. 22.678 + 233 =
  23. 23.364 + 608 =
  24. 24.297 + 471 =
  25. 25.362 + 273 =
  26. 26.414 + 384 =
  27. 27.710 − 238 =
  28. 28.416 + 594 =
  29. 29.642 − 316 =
  30. 30.369 + 289 =
  31. 31.652 + 169 =
  32. 32.433 + 638 =
  33. 33.761 + 139 =
  34. 34.748 − 298 =
  35. 35.744 + 436 =
  36. 36.539 − 395 =
  37. 37.769 − 264 =
  38. 38.276 + 481 =
  39. 39.607 + 558 =
  40. 40.885 − 161 =

Answer key

  1. 113
  2. 768
  3. 760
  4. 1040
  5. 295
  6. 713
  7. 1324
  8. 528
  9. 489
  10. 419
  11. 175
  12. 584
  13. 600
  14. 185
  15. 159
  16. 130
  17. 241
  18. 229
  19. 367
  20. 213
  21. 524
  22. 911
  23. 972
  24. 768
  25. 635
  26. 798
  27. 472
  28. 1010
  29. 326
  30. 658
  31. 821
  32. 1071
  33. 900
  34. 450
  35. 1180
  36. 144
  37. 505
  38. 757
  39. 1165
  40. 724

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