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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 450 · 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. 1.365 + 37 =
  2. 2.37 + 37 =
  3. 3.254 + 97 =
  4. 4.318 + 49 =
  5. 5.409 + 38 =
  6. 6.113 + 37 =
  7. 7.334 + 29 =
  8. 8.204 + 97 =
  9. 9.362 + 49 =
  10. 10.33 + 57 =
  11. 11.229 + 17 =
  12. 12.422 + 37 =
  13. 13.368 + 48 =
  14. 14.93 + 79 =
  15. 15.135 + 29 =
  16. 16.149 + 98 =
  17. 17.265 + 29 =
  18. 18.98 + 57 =
  19. 19.182 + 57 =
  20. 20.257 + 47 =
  21. 21.349 + 99 =
  22. 22.151 + 47 =
  23. 23.134 + 28 =
  24. 24.381 + 17 =
  25. 25.338 + 27 =
  26. 26.338 + 17 =
  27. 27.180 + 78 =
  28. 28.275 + 87 =
  29. 29.339 + 28 =
  30. 30.41 + 29 =
  31. 31.216 + 48 =
  32. 32.63 + 68 =
  33. 33.63 + 89 =
  34. 34.450 + 47 =
  35. 35.59 + 58 =
  36. 36.163 + 39 =
  37. 37.45 + 97 =
  38. 38.63 + 58 =
  39. 39.439 + 68 =
  40. 40.157 + 69 =

Answer key

  1. 402
  2. 74
  3. 351
  4. 367
  5. 447
  6. 150
  7. 363
  8. 301
  9. 411
  10. 90
  11. 246
  12. 459
  13. 416
  14. 172
  15. 164
  16. 247
  17. 294
  18. 155
  19. 239
  20. 304
  21. 448
  22. 198
  23. 162
  24. 398
  25. 365
  26. 355
  27. 258
  28. 362
  29. 367
  30. 70
  31. 264
  32. 131
  33. 152
  34. 497
  35. 117
  36. 202
  37. 142
  38. 121
  39. 507
  40. 226

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