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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 132 · 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. 1.132 + 631 =
  2. 2.159 + 379 =
  3. 3.621 − 157 =
  4. 4.274 + 633 =
  5. 5.574 + 231 =
  6. 6.703 − 231 =
  7. 7.516 + 461 =
  8. 8.451 + 155 =
  9. 9.932 − 394 =
  10. 10.946 − 603 =
  11. 11.503 + 387 =
  12. 12.616 − 147 =
  13. 13.295 + 413 =
  14. 14.466 + 518 =
  15. 15.394 + 204 =
  16. 16.624 − 294 =
  17. 17.351 + 255 =
  18. 18.386 + 491 =
  19. 19.262 + 187 =
  20. 20.867 − 147 =
  21. 21.881 − 161 =
  22. 22.154 + 338 =
  23. 23.656 + 521 =
  24. 24.925 − 231 =
  25. 25.427 + 346 =
  26. 26.721 − 496 =
  27. 27.864 − 228 =
  28. 28.543 + 601 =
  29. 29.799 − 513 =
  30. 30.476 − 309 =
  31. 31.642 + 661 =
  32. 32.247 + 407 =
  33. 33.505 + 212 =
  34. 34.733 + 251 =
  35. 35.721 − 241 =
  36. 36.160 + 592 =
  37. 37.153 + 201 =
  38. 38.536 − 419 =
  39. 39.774 − 216 =
  40. 40.765 + 414 =

Answer key

  1. 763
  2. 538
  3. 464
  4. 907
  5. 805
  6. 472
  7. 977
  8. 606
  9. 538
  10. 343
  11. 890
  12. 469
  13. 708
  14. 984
  15. 598
  16. 330
  17. 606
  18. 877
  19. 449
  20. 720
  21. 720
  22. 492
  23. 1177
  24. 694
  25. 773
  26. 225
  27. 636
  28. 1144
  29. 286
  30. 167
  31. 1303
  32. 654
  33. 717
  34. 984
  35. 480
  36. 752
  37. 354
  38. 117
  39. 558
  40. 1179

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