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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 744 · 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. 1.427 − 234 =
  2. 2.644 + 339 =
  3. 3.776 + 666 =
  4. 4.300 + 671 =
  5. 5.198 + 435 =
  6. 6.422 − 117 =
  7. 7.398 + 598 =
  8. 8.652 − 282 =
  9. 9.449 + 216 =
  10. 10.142 + 644 =
  11. 11.746 + 441 =
  12. 12.242 + 169 =
  13. 13.496 + 521 =
  14. 14.530 + 601 =
  15. 15.484 + 531 =
  16. 16.955 − 153 =
  17. 17.914 − 724 =
  18. 18.650 + 652 =
  19. 19.467 − 322 =
  20. 20.605 + 527 =
  21. 21.494 − 161 =
  22. 22.319 + 473 =
  23. 23.350 + 368 =
  24. 24.717 + 171 =
  25. 25.805 − 242 =
  26. 26.346 + 284 =
  27. 27.589 − 475 =
  28. 28.173 + 382 =
  29. 29.191 + 249 =
  30. 30.280 + 286 =
  31. 31.362 + 682 =
  32. 32.397 + 359 =
  33. 33.435 − 131 =
  34. 34.648 − 455 =
  35. 35.218 + 551 =
  36. 36.426 + 212 =
  37. 37.250 + 142 =
  38. 38.337 + 679 =
  39. 39.725 + 486 =
  40. 40.756 − 547 =

Answer key

  1. 193
  2. 983
  3. 1442
  4. 971
  5. 633
  6. 305
  7. 996
  8. 370
  9. 665
  10. 786
  11. 1187
  12. 411
  13. 1017
  14. 1131
  15. 1015
  16. 802
  17. 190
  18. 1302
  19. 145
  20. 1132
  21. 333
  22. 792
  23. 718
  24. 888
  25. 563
  26. 630
  27. 114
  28. 555
  29. 440
  30. 566
  31. 1044
  32. 756
  33. 304
  34. 193
  35. 769
  36. 638
  37. 392
  38. 1016
  39. 1211
  40. 209

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