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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 131 · 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. 1.539 + 128 =
  2. 2.257 + 124 =
  3. 3.461 − 301 =
  4. 4.725 − 181 =
  5. 5.893 − 466 =
  6. 6.352 + 685 =
  7. 7.421 − 267 =
  8. 8.505 + 334 =
  9. 9.431 − 261 =
  10. 10.684 − 209 =
  11. 11.474 + 184 =
  12. 12.578 + 365 =
  13. 13.497 − 314 =
  14. 14.578 + 538 =
  15. 15.765 + 316 =
  16. 16.559 + 121 =
  17. 17.532 + 677 =
  18. 18.735 − 246 =
  19. 19.819 − 541 =
  20. 20.517 + 226 =
  21. 21.807 − 645 =
  22. 22.455 − 208 =
  23. 23.437 + 467 =
  24. 24.711 + 195 =
  25. 25.989 − 294 =
  26. 26.754 − 326 =
  27. 27.781 − 161 =
  28. 28.683 + 301 =
  29. 29.421 + 211 =
  30. 30.219 + 305 =
  31. 31.418 − 291 =
  32. 32.412 − 271 =
  33. 33.831 − 449 =
  34. 34.977 − 475 =
  35. 35.238 + 497 =
  36. 36.599 + 128 =
  37. 37.673 + 311 =
  38. 38.881 − 241 =
  39. 39.750 − 244 =
  40. 40.512 + 615 =

Answer key

  1. 667
  2. 381
  3. 160
  4. 544
  5. 427
  6. 1037
  7. 154
  8. 839
  9. 170
  10. 475
  11. 658
  12. 943
  13. 183
  14. 1116
  15. 1081
  16. 680
  17. 1209
  18. 489
  19. 278
  20. 743
  21. 162
  22. 247
  23. 904
  24. 906
  25. 695
  26. 428
  27. 620
  28. 984
  29. 632
  30. 524
  31. 127
  32. 141
  33. 382
  34. 502
  35. 735
  36. 727
  37. 984
  38. 640
  39. 506
  40. 1127

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