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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 85 · 40 questions
TalentJR

The fast method (Round up, then fix): Round the number ending in 7, 8 or 9 up to the next ten: 39 → 40. Add the round number. Take away the extra you added (here 1).

NameDateTime takenScore ___ / 40
  1. 1.483 + 39 =
  2. 2.39 + 59 =
  3. 3.422 + 19 =
  4. 4.116 + 18 =
  5. 5.45 + 18 =
  6. 6.453 + 17 =
  7. 7.360 + 49 =
  8. 8.132 + 89 =
  9. 9.186 + 47 =
  10. 10.99 + 57 =
  11. 11.311 + 17 =
  12. 12.37 + 68 =
  13. 13.116 + 29 =
  14. 14.64 + 18 =
  15. 15.155 + 38 =
  16. 16.30 + 59 =
  17. 17.349 + 29 =
  18. 18.118 + 47 =
  19. 19.483 + 48 =
  20. 20.46 + 57 =
  21. 21.207 + 57 =
  22. 22.144 + 89 =
  23. 23.238 + 37 =
  24. 24.121 + 77 =
  25. 25.53 + 87 =
  26. 26.43 + 19 =
  27. 27.260 + 68 =
  28. 28.243 + 39 =
  29. 29.490 + 39 =
  30. 30.370 + 69 =
  31. 31.279 + 59 =
  32. 32.329 + 17 =
  33. 33.382 + 89 =
  34. 34.273 + 48 =
  35. 35.327 + 79 =
  36. 36.100 + 47 =
  37. 37.292 + 47 =
  38. 38.480 + 89 =
  39. 39.294 + 17 =
  40. 40.233 + 47 =

Answer key

  1. 522
  2. 98
  3. 441
  4. 134
  5. 63
  6. 470
  7. 409
  8. 221
  9. 233
  10. 156
  11. 328
  12. 105
  13. 145
  14. 82
  15. 193
  16. 89
  17. 378
  18. 165
  19. 531
  20. 103
  21. 264
  22. 233
  23. 275
  24. 198
  25. 140
  26. 62
  27. 328
  28. 282
  29. 529
  30. 439
  31. 338
  32. 346
  33. 471
  34. 321
  35. 406
  36. 147
  37. 339
  38. 569
  39. 311
  40. 280

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