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Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 767 · 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. 1.748 − 597 =
  2. 2.968 − 699 =
  3. 3.789 − 339 =
  4. 4.893 − 419 =
  5. 5.901 − 299 =
  6. 6.968 − 797 =
  7. 7.899 − 418 =
  8. 8.270 − 227 =
  9. 9.592 − 397 =
  10. 10.945 − 647 =
  11. 11.588 − 498 =
  12. 12.752 − 599 =
  13. 13.438 − 288 =
  14. 14.688 − 299 =
  15. 15.459 − 399 =
  16. 16.457 − 419 =
  17. 17.441 − 398 =
  18. 18.630 − 499 =
  19. 19.260 − 199 =
  20. 20.731 − 649 =
  21. 21.893 − 197 =
  22. 22.344 − 179 =
  23. 23.697 − 297 =
  24. 24.442 − 139 =
  25. 25.838 − 269 =
  26. 26.623 − 559 =
  27. 27.877 − 599 =
  28. 28.677 − 658 =
  29. 29.849 − 697 =
  30. 30.683 − 559 =
  31. 31.585 − 197 =
  32. 32.910 − 209 =
  33. 33.862 − 378 =
  34. 34.990 − 799 =
  35. 35.717 − 189 =
  36. 36.864 − 798 =
  37. 37.623 − 598 =
  38. 38.762 − 207 =
  39. 39.665 − 299 =
  40. 40.747 − 697 =

Answer key

  1. 151
  2. 269
  3. 450
  4. 474
  5. 602
  6. 171
  7. 481
  8. 43
  9. 195
  10. 298
  11. 90
  12. 153
  13. 150
  14. 389
  15. 60
  16. 38
  17. 43
  18. 131
  19. 61
  20. 82
  21. 696
  22. 165
  23. 400
  24. 303
  25. 569
  26. 64
  27. 278
  28. 19
  29. 152
  30. 124
  31. 388
  32. 701
  33. 484
  34. 191
  35. 528
  36. 66
  37. 25
  38. 555
  39. 366
  40. 50

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