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Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 664 · 40 questions
TalentJR

How to do it in your head (Round up, add back): Round the number you take away up to the next ten or hundred: 297 → 300 (3 too many). Take away the round number. Add back the extra, because you took away too much.

NameDateTime takenScore ___ / 40
  1. 1.956 − 688 =
  2. 2.475 − 399 =
  3. 3.998 − 798 =
  4. 4.868 − 698 =
  5. 5.880 − 397 =
  6. 6.453 − 297 =
  7. 7.958 − 569 =
  8. 8.334 − 298 =
  9. 9.829 − 637 =
  10. 10.579 − 397 =
  11. 11.529 − 198 =
  12. 12.879 − 798 =
  13. 13.610 − 247 =
  14. 14.502 − 408 =
  15. 15.634 − 597 =
  16. 16.657 − 597 =
  17. 17.692 − 539 =
  18. 18.897 − 618 =
  19. 19.599 − 397 =
  20. 20.926 − 497 =
  21. 21.782 − 197 =
  22. 22.805 − 659 =
  23. 23.369 − 297 =
  24. 24.738 − 489 =
  25. 25.945 − 559 =
  26. 26.452 − 199 =
  27. 27.888 − 697 =
  28. 28.904 − 199 =
  29. 29.462 − 299 =
  30. 30.951 − 658 =
  31. 31.866 − 498 =
  32. 32.921 − 449 =
  33. 33.820 − 697 =
  34. 34.853 − 797 =
  35. 35.794 − 497 =
  36. 36.519 − 199 =
  37. 37.819 − 179 =
  38. 38.963 − 799 =
  39. 39.568 − 499 =
  40. 40.945 − 798 =

Answer key

  1. 268
  2. 76
  3. 200
  4. 170
  5. 483
  6. 156
  7. 389
  8. 36
  9. 192
  10. 182
  11. 331
  12. 81
  13. 363
  14. 94
  15. 37
  16. 60
  17. 153
  18. 279
  19. 202
  20. 429
  21. 585
  22. 146
  23. 72
  24. 249
  25. 386
  26. 253
  27. 191
  28. 705
  29. 163
  30. 293
  31. 368
  32. 472
  33. 123
  34. 56
  35. 297
  36. 320
  37. 640
  38. 164
  39. 69
  40. 147

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