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Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 879 · 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. 1.442 − 197 =
  2. 2.384 − 179 =
  3. 3.818 − 797 =
  4. 4.829 − 548 =
  5. 5.922 − 507 =
  6. 6.840 − 498 =
  7. 7.436 − 159 =
  8. 8.953 − 697 =
  9. 9.880 − 659 =
  10. 10.549 − 398 =
  11. 11.873 − 797 =
  12. 12.692 − 599 =
  13. 13.863 − 187 =
  14. 14.298 − 198 =
  15. 15.573 − 397 =
  16. 16.902 − 798 =
  17. 17.960 − 699 =
  18. 18.655 − 399 =
  19. 19.772 − 599 =
  20. 20.819 − 688 =
  21. 21.771 − 508 =
  22. 22.452 − 358 =
  23. 23.983 − 297 =
  24. 24.883 − 699 =
  25. 25.697 − 597 =
  26. 26.953 − 799 =
  27. 27.790 − 599 =
  28. 28.838 − 799 =
  29. 29.302 − 278 =
  30. 30.703 − 628 =
  31. 31.609 − 348 =
  32. 32.915 − 298 =
  33. 33.624 − 398 =
  34. 34.971 − 798 =
  35. 35.867 − 798 =
  36. 36.639 − 119 =
  37. 37.768 − 697 =
  38. 38.702 − 479 =
  39. 39.713 − 599 =
  40. 40.681 − 598 =

Answer key

  1. 245
  2. 205
  3. 21
  4. 281
  5. 415
  6. 342
  7. 277
  8. 256
  9. 221
  10. 151
  11. 76
  12. 93
  13. 676
  14. 100
  15. 176
  16. 104
  17. 261
  18. 256
  19. 173
  20. 131
  21. 263
  22. 94
  23. 686
  24. 184
  25. 100
  26. 154
  27. 191
  28. 39
  29. 24
  30. 75
  31. 261
  32. 617
  33. 226
  34. 173
  35. 69
  36. 520
  37. 71
  38. 223
  39. 114
  40. 83

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