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Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 483 · 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. 1.952 − 577 =
  2. 2.635 − 497 =
  3. 3.870 − 118 =
  4. 4.823 − 449 =
  5. 5.829 − 497 =
  6. 6.468 − 198 =
  7. 7.887 − 697 =
  8. 8.426 − 398 =
  9. 9.995 − 499 =
  10. 10.563 − 547 =
  11. 11.947 − 599 =
  12. 12.769 − 199 =
  13. 13.331 − 187 =
  14. 14.675 − 497 =
  15. 15.973 − 199 =
  16. 16.595 − 299 =
  17. 17.610 − 498 =
  18. 18.624 − 598 =
  19. 19.853 − 797 =
  20. 20.956 − 297 =
  21. 21.425 − 347 =
  22. 22.876 − 197 =
  23. 23.670 − 618 =
  24. 24.760 − 697 =
  25. 25.901 − 697 =
  26. 26.408 − 299 =
  27. 27.961 − 797 =
  28. 28.660 − 598 =
  29. 29.710 − 397 =
  30. 30.534 − 438 =
  31. 31.758 − 368 =
  32. 32.807 − 498 =
  33. 33.914 − 237 =
  34. 34.788 − 177 =
  35. 35.651 − 568 =
  36. 36.445 − 398 =
  37. 37.925 − 799 =
  38. 38.736 − 629 =
  39. 39.986 − 697 =
  40. 40.556 − 399 =

Answer key

  1. 375
  2. 138
  3. 752
  4. 374
  5. 332
  6. 270
  7. 190
  8. 28
  9. 496
  10. 16
  11. 348
  12. 570
  13. 144
  14. 178
  15. 774
  16. 296
  17. 112
  18. 26
  19. 56
  20. 659
  21. 78
  22. 679
  23. 52
  24. 63
  25. 204
  26. 109
  27. 164
  28. 62
  29. 313
  30. 96
  31. 390
  32. 309
  33. 677
  34. 611
  35. 83
  36. 47
  37. 126
  38. 107
  39. 289
  40. 157

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