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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 127 · 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. 1.730 − 544 =
  2. 2.428 − 172 =
  3. 3.695 − 379 =
  4. 4.458 − 224 =
  5. 5.436 + 168 =
  6. 6.449 − 216 =
  7. 7.711 − 264 =
  8. 8.344 + 617 =
  9. 9.636 − 478 =
  10. 10.162 + 379 =
  11. 11.750 − 432 =
  12. 12.922 − 361 =
  13. 13.616 + 417 =
  14. 14.214 + 405 =
  15. 15.635 − 301 =
  16. 16.634 − 292 =
  17. 17.695 + 443 =
  18. 18.366 + 462 =
  19. 19.150 + 232 =
  20. 20.219 + 472 =
  21. 21.210 + 621 =
  22. 22.966 − 699 =
  23. 23.640 + 245 =
  24. 24.139 + 316 =
  25. 25.608 + 547 =
  26. 26.431 + 509 =
  27. 27.392 + 502 =
  28. 28.253 + 563 =
  29. 29.521 − 223 =
  30. 30.613 − 447 =
  31. 31.421 − 282 =
  32. 32.643 − 181 =
  33. 33.356 + 228 =
  34. 34.694 − 482 =
  35. 35.882 − 326 =
  36. 36.517 − 293 =
  37. 37.524 + 499 =
  38. 38.369 + 127 =
  39. 39.378 + 672 =
  40. 40.445 + 655 =

Answer key

  1. 186
  2. 256
  3. 316
  4. 234
  5. 604
  6. 233
  7. 447
  8. 961
  9. 158
  10. 541
  11. 318
  12. 561
  13. 1033
  14. 619
  15. 334
  16. 342
  17. 1138
  18. 828
  19. 382
  20. 691
  21. 831
  22. 267
  23. 885
  24. 455
  25. 1155
  26. 940
  27. 894
  28. 816
  29. 298
  30. 166
  31. 139
  32. 462
  33. 584
  34. 212
  35. 556
  36. 224
  37. 1023
  38. 496
  39. 1050
  40. 1100

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