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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 108 · 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. 1.446 − 197 =
  2. 2.700 + 377 =
  3. 3.204 + 654 =
  4. 4.616 + 609 =
  5. 5.632 − 377 =
  6. 6.433 − 223 =
  7. 7.266 + 301 =
  8. 8.470 − 192 =
  9. 9.209 + 485 =
  10. 10.838 − 691 =
  11. 11.440 − 188 =
  12. 12.578 + 684 =
  13. 13.673 + 265 =
  14. 14.788 + 181 =
  15. 15.521 + 133 =
  16. 16.523 + 132 =
  17. 17.426 + 255 =
  18. 18.286 + 317 =
  19. 19.631 − 181 =
  20. 20.600 + 558 =
  21. 21.701 − 428 =
  22. 22.441 − 201 =
  23. 23.278 + 307 =
  24. 24.867 − 438 =
  25. 25.520 − 257 =
  26. 26.521 − 302 =
  27. 27.655 − 167 =
  28. 28.463 + 648 =
  29. 29.206 + 413 =
  30. 30.533 − 227 =
  31. 31.740 − 351 =
  32. 32.483 + 258 =
  33. 33.556 + 357 =
  34. 34.300 + 379 =
  35. 35.576 − 176 =
  36. 36.261 + 239 =
  37. 37.533 − 336 =
  38. 38.434 − 219 =
  39. 39.576 + 406 =
  40. 40.564 + 646 =

Answer key

  1. 249
  2. 1077
  3. 858
  4. 1225
  5. 255
  6. 210
  7. 567
  8. 278
  9. 694
  10. 147
  11. 252
  12. 1262
  13. 938
  14. 969
  15. 654
  16. 655
  17. 681
  18. 603
  19. 450
  20. 1158
  21. 273
  22. 240
  23. 585
  24. 429
  25. 263
  26. 219
  27. 488
  28. 1111
  29. 619
  30. 306
  31. 389
  32. 741
  33. 913
  34. 679
  35. 400
  36. 500
  37. 197
  38. 215
  39. 982
  40. 1210

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