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Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 301 · 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. 1.848 − 698 =
  2. 2.698 − 299 =
  3. 3.758 − 298 =
  4. 4.942 − 588 =
  5. 5.724 − 597 =
  6. 6.413 − 198 =
  7. 7.818 − 337 =
  8. 8.768 − 497 =
  9. 9.944 − 138 =
  10. 10.525 − 448 =
  11. 11.823 − 489 =
  12. 12.426 − 399 =
  13. 13.824 − 499 =
  14. 14.899 − 798 =
  15. 15.869 − 697 =
  16. 16.847 − 299 =
  17. 17.489 − 297 =
  18. 18.951 − 459 =
  19. 19.645 − 628 =
  20. 20.738 − 398 =
  21. 21.772 − 597 =
  22. 22.904 − 199 =
  23. 23.925 − 277 =
  24. 24.726 − 697 =
  25. 25.405 − 349 =
  26. 26.355 − 297 =
  27. 27.620 − 598 =
  28. 28.625 − 357 =
  29. 29.766 − 199 =
  30. 30.488 − 207 =
  31. 31.720 − 649 =
  32. 32.884 − 549 =
  33. 33.968 − 548 =
  34. 34.709 − 499 =
  35. 35.671 − 598 =
  36. 36.382 − 199 =
  37. 37.909 − 179 =
  38. 38.903 − 799 =
  39. 39.922 − 279 =
  40. 40.863 − 498 =

Answer key

  1. 150
  2. 399
  3. 460
  4. 354
  5. 127
  6. 215
  7. 481
  8. 271
  9. 806
  10. 77
  11. 334
  12. 27
  13. 325
  14. 101
  15. 172
  16. 548
  17. 192
  18. 492
  19. 17
  20. 340
  21. 175
  22. 705
  23. 648
  24. 29
  25. 56
  26. 58
  27. 22
  28. 268
  29. 567
  30. 281
  31. 71
  32. 335
  33. 420
  34. 210
  35. 73
  36. 183
  37. 730
  38. 104
  39. 643
  40. 365

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