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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 200 · 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. 1.316 + 411 =
  2. 2.652 − 473 =
  3. 3.664 + 292 =
  4. 4.708 + 346 =
  5. 5.924 − 151 =
  6. 6.619 − 149 =
  7. 7.773 + 481 =
  8. 8.860 − 359 =
  9. 9.195 + 545 =
  10. 10.184 + 374 =
  11. 11.828 − 244 =
  12. 12.548 + 329 =
  13. 13.483 − 145 =
  14. 14.448 + 444 =
  15. 15.139 + 282 =
  16. 16.707 + 456 =
  17. 17.411 + 399 =
  18. 18.438 − 271 =
  19. 19.480 + 472 =
  20. 20.472 − 206 =
  21. 21.348 + 306 =
  22. 22.442 + 445 =
  23. 23.433 − 145 =
  24. 24.785 − 187 =
  25. 25.599 − 393 =
  26. 26.403 + 132 =
  27. 27.547 − 182 =
  28. 28.386 + 209 =
  29. 29.641 − 361 =
  30. 30.702 + 445 =
  31. 31.475 − 203 =
  32. 32.138 + 601 =
  33. 33.837 − 362 =
  34. 34.165 + 273 =
  35. 35.479 − 162 =
  36. 36.490 − 256 =
  37. 37.462 − 161 =
  38. 38.587 + 179 =
  39. 39.779 + 239 =
  40. 40.186 + 548 =

Answer key

  1. 727
  2. 179
  3. 956
  4. 1054
  5. 773
  6. 470
  7. 1254
  8. 501
  9. 740
  10. 558
  11. 584
  12. 877
  13. 338
  14. 892
  15. 421
  16. 1163
  17. 810
  18. 167
  19. 952
  20. 266
  21. 654
  22. 887
  23. 288
  24. 598
  25. 206
  26. 535
  27. 365
  28. 595
  29. 280
  30. 1147
  31. 272
  32. 739
  33. 475
  34. 438
  35. 317
  36. 234
  37. 301
  38. 766
  39. 1018
  40. 734

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