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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 199 · 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. 1.500 − 136 =
  2. 2.947 − 495 =
  3. 3.253 + 481 =
  4. 4.716 − 258 =
  5. 5.417 + 531 =
  6. 6.582 − 242 =
  7. 7.131 + 158 =
  8. 8.208 + 433 =
  9. 9.386 + 601 =
  10. 10.554 + 343 =
  11. 11.192 + 566 =
  12. 12.743 + 448 =
  13. 13.642 − 534 =
  14. 14.550 + 191 =
  15. 15.450 + 391 =
  16. 16.758 + 487 =
  17. 17.900 − 781 =
  18. 18.964 − 401 =
  19. 19.472 + 521 =
  20. 20.454 − 144 =
  21. 21.587 − 368 =
  22. 22.409 + 642 =
  23. 23.716 − 577 =
  24. 24.328 + 167 =
  25. 25.217 + 363 =
  26. 26.485 + 674 =
  27. 27.688 − 469 =
  28. 28.547 + 649 =
  29. 29.905 − 351 =
  30. 30.552 + 412 =
  31. 31.468 + 346 =
  32. 32.511 − 258 =
  33. 33.909 − 397 =
  34. 34.575 − 127 =
  35. 35.578 + 163 =
  36. 36.922 − 292 =
  37. 37.546 + 353 =
  38. 38.887 − 624 =
  39. 39.596 − 265 =
  40. 40.716 − 158 =

Answer key

  1. 364
  2. 452
  3. 734
  4. 458
  5. 948
  6. 340
  7. 289
  8. 641
  9. 987
  10. 897
  11. 758
  12. 1191
  13. 108
  14. 741
  15. 841
  16. 1245
  17. 119
  18. 563
  19. 993
  20. 310
  21. 219
  22. 1051
  23. 139
  24. 495
  25. 580
  26. 1159
  27. 219
  28. 1196
  29. 554
  30. 964
  31. 814
  32. 253
  33. 512
  34. 448
  35. 741
  36. 630
  37. 899
  38. 263
  39. 331
  40. 558

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