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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 982 · 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. 1.142 + 224 =
  2. 2.935 − 763 =
  3. 3.539 − 424 =
  4. 4.744 − 432 =
  5. 5.871 − 458 =
  6. 6.588 + 358 =
  7. 7.236 + 151 =
  8. 8.502 − 278 =
  9. 9.842 − 182 =
  10. 10.173 + 661 =
  11. 11.852 − 475 =
  12. 12.444 − 221 =
  13. 13.939 − 259 =
  14. 14.490 − 274 =
  15. 15.748 + 457 =
  16. 16.770 − 191 =
  17. 17.308 + 614 =
  18. 18.759 − 414 =
  19. 19.741 + 513 =
  20. 20.498 + 518 =
  21. 21.640 + 167 =
  22. 22.175 + 293 =
  23. 23.670 − 191 =
  24. 24.234 + 573 =
  25. 25.434 + 395 =
  26. 26.419 − 118 =
  27. 27.560 − 172 =
  28. 28.855 − 134 =
  29. 29.732 − 183 =
  30. 30.571 − 441 =
  31. 31.554 − 283 =
  32. 32.864 − 471 =
  33. 33.818 − 531 =
  34. 34.543 + 511 =
  35. 35.424 + 126 =
  36. 36.525 − 369 =
  37. 37.681 − 439 =
  38. 38.558 + 362 =
  39. 39.253 + 661 =
  40. 40.549 − 141 =

Answer key

  1. 366
  2. 172
  3. 115
  4. 312
  5. 413
  6. 946
  7. 387
  8. 224
  9. 660
  10. 834
  11. 377
  12. 223
  13. 680
  14. 216
  15. 1205
  16. 579
  17. 922
  18. 345
  19. 1254
  20. 1016
  21. 807
  22. 468
  23. 479
  24. 807
  25. 829
  26. 301
  27. 388
  28. 721
  29. 549
  30. 130
  31. 271
  32. 393
  33. 287
  34. 1054
  35. 550
  36. 156
  37. 242
  38. 920
  39. 914
  40. 408

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