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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 345 · 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. 1.477 + 79 =
  2. 2.115 + 19 =
  3. 3.110 + 37 =
  4. 4.470 + 97 =
  5. 5.313 + 28 =
  6. 6.327 + 27 =
  7. 7.478 + 77 =
  8. 8.90 + 18 =
  9. 9.365 + 47 =
  10. 10.479 + 68 =
  11. 11.160 + 47 =
  12. 12.412 + 27 =
  13. 13.124 + 29 =
  14. 14.266 + 17 =
  15. 15.361 + 98 =
  16. 16.279 + 87 =
  17. 17.26 + 89 =
  18. 18.166 + 49 =
  19. 19.54 + 17 =
  20. 20.320 + 59 =
  21. 21.261 + 69 =
  22. 22.446 + 18 =
  23. 23.351 + 87 =
  24. 24.45 + 37 =
  25. 25.372 + 98 =
  26. 26.274 + 89 =
  27. 27.162 + 27 =
  28. 28.475 + 78 =
  29. 29.405 + 18 =
  30. 30.339 + 87 =
  31. 31.379 + 38 =
  32. 32.449 + 28 =
  33. 33.47 + 18 =
  34. 34.295 + 27 =
  35. 35.351 + 29 =
  36. 36.54 + 17 =
  37. 37.326 + 57 =
  38. 38.295 + 38 =
  39. 39.136 + 27 =
  40. 40.284 + 88 =

Answer key

  1. 556
  2. 134
  3. 147
  4. 567
  5. 341
  6. 354
  7. 555
  8. 108
  9. 412
  10. 547
  11. 207
  12. 439
  13. 153
  14. 283
  15. 459
  16. 366
  17. 115
  18. 215
  19. 71
  20. 379
  21. 330
  22. 464
  23. 438
  24. 82
  25. 470
  26. 363
  27. 189
  28. 553
  29. 423
  30. 426
  31. 417
  32. 477
  33. 65
  34. 322
  35. 380
  36. 71
  37. 383
  38. 333
  39. 163
  40. 372

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