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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 822 · 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. 1.480 − 227 =
  2. 2.557 − 311 =
  3. 3.367 + 332 =
  4. 4.475 − 193 =
  5. 5.761 + 212 =
  6. 6.884 − 183 =
  7. 7.405 + 251 =
  8. 8.304 + 293 =
  9. 9.286 + 348 =
  10. 10.536 − 251 =
  11. 11.363 + 315 =
  12. 12.546 − 177 =
  13. 13.898 − 213 =
  14. 14.553 − 327 =
  15. 15.534 + 653 =
  16. 16.418 − 134 =
  17. 17.780 − 459 =
  18. 18.310 + 228 =
  19. 19.695 + 642 =
  20. 20.884 − 326 =
  21. 21.457 − 144 =
  22. 22.192 + 519 =
  23. 23.772 + 615 =
  24. 24.246 + 151 =
  25. 25.646 − 381 =
  26. 26.174 + 526 =
  27. 27.525 − 233 =
  28. 28.902 − 189 =
  29. 29.470 − 295 =
  30. 30.542 + 131 =
  31. 31.532 + 541 =
  32. 32.322 + 149 =
  33. 33.156 + 338 =
  34. 34.430 + 427 =
  35. 35.946 − 188 =
  36. 36.630 + 341 =
  37. 37.826 − 227 =
  38. 38.222 + 558 =
  39. 39.618 + 628 =
  40. 40.171 + 462 =

Answer key

  1. 253
  2. 246
  3. 699
  4. 282
  5. 973
  6. 701
  7. 656
  8. 597
  9. 634
  10. 285
  11. 678
  12. 369
  13. 685
  14. 226
  15. 1187
  16. 284
  17. 321
  18. 538
  19. 1337
  20. 558
  21. 313
  22. 711
  23. 1387
  24. 397
  25. 265
  26. 700
  27. 292
  28. 713
  29. 175
  30. 673
  31. 1073
  32. 471
  33. 494
  34. 857
  35. 758
  36. 971
  37. 599
  38. 780
  39. 1246
  40. 633

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