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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 551 · 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. 1.116 + 29 =
  2. 2.199 + 39 =
  3. 3.212 + 19 =
  4. 4.47 + 17 =
  5. 5.296 + 49 =
  6. 6.37 + 77 =
  7. 7.285 + 67 =
  8. 8.315 + 59 =
  9. 9.482 + 38 =
  10. 10.336 + 67 =
  11. 11.151 + 37 =
  12. 12.471 + 87 =
  13. 13.440 + 47 =
  14. 14.265 + 19 =
  15. 15.88 + 17 =
  16. 16.450 + 27 =
  17. 17.464 + 69 =
  18. 18.397 + 78 =
  19. 19.40 + 88 =
  20. 20.400 + 88 =
  21. 21.262 + 99 =
  22. 22.300 + 88 =
  23. 23.134 + 67 =
  24. 24.487 + 49 =
  25. 25.265 + 98 =
  26. 26.177 + 27 =
  27. 27.113 + 29 =
  28. 28.88 + 97 =
  29. 29.329 + 27 =
  30. 30.443 + 37 =
  31. 31.45 + 57 =
  32. 32.185 + 17 =
  33. 33.132 + 98 =
  34. 34.49 + 57 =
  35. 35.351 + 39 =
  36. 36.249 + 37 =
  37. 37.306 + 38 =
  38. 38.112 + 28 =
  39. 39.490 + 88 =
  40. 40.284 + 78 =

Answer key

  1. 145
  2. 238
  3. 231
  4. 64
  5. 345
  6. 114
  7. 352
  8. 374
  9. 520
  10. 403
  11. 188
  12. 558
  13. 487
  14. 284
  15. 105
  16. 477
  17. 533
  18. 475
  19. 128
  20. 488
  21. 361
  22. 388
  23. 201
  24. 536
  25. 363
  26. 204
  27. 142
  28. 185
  29. 356
  30. 480
  31. 102
  32. 202
  33. 230
  34. 106
  35. 390
  36. 286
  37. 344
  38. 140
  39. 578
  40. 362

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