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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 38 · 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. 1.91 + 89 =
  2. 2.427 + 78 =
  3. 3.137 + 88 =
  4. 4.278 + 99 =
  5. 5.216 + 68 =
  6. 6.214 + 88 =
  7. 7.252 + 88 =
  8. 8.244 + 99 =
  9. 9.106 + 27 =
  10. 10.445 + 67 =
  11. 11.404 + 48 =
  12. 12.153 + 39 =
  13. 13.191 + 79 =
  14. 14.179 + 39 =
  15. 15.285 + 99 =
  16. 16.60 + 49 =
  17. 17.130 + 39 =
  18. 18.418 + 69 =
  19. 19.52 + 78 =
  20. 20.154 + 79 =
  21. 21.372 + 59 =
  22. 22.254 + 59 =
  23. 23.125 + 79 =
  24. 24.142 + 77 =
  25. 25.126 + 17 =
  26. 26.210 + 39 =
  27. 27.46 + 39 =
  28. 28.105 + 47 =
  29. 29.325 + 88 =
  30. 30.28 + 17 =
  31. 31.244 + 97 =
  32. 32.331 + 69 =
  33. 33.400 + 59 =
  34. 34.207 + 77 =
  35. 35.31 + 67 =
  36. 36.474 + 27 =
  37. 37.103 + 67 =
  38. 38.308 + 29 =
  39. 39.326 + 19 =
  40. 40.92 + 47 =

Answer key

  1. 180
  2. 505
  3. 225
  4. 377
  5. 284
  6. 302
  7. 340
  8. 343
  9. 133
  10. 512
  11. 452
  12. 192
  13. 270
  14. 218
  15. 384
  16. 109
  17. 169
  18. 487
  19. 130
  20. 233
  21. 431
  22. 313
  23. 204
  24. 219
  25. 143
  26. 249
  27. 85
  28. 152
  29. 413
  30. 45
  31. 341
  32. 400
  33. 459
  34. 284
  35. 98
  36. 501
  37. 170
  38. 337
  39. 345
  40. 139

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