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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 470 · 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. 1.472 + 79 =
  2. 2.301 + 48 =
  3. 3.66 + 38 =
  4. 4.194 + 87 =
  5. 5.370 + 37 =
  6. 6.308 + 99 =
  7. 7.117 + 37 =
  8. 8.230 + 49 =
  9. 9.70 + 47 =
  10. 10.135 + 89 =
  11. 11.269 + 68 =
  12. 12.116 + 97 =
  13. 13.391 + 99 =
  14. 14.186 + 97 =
  15. 15.129 + 79 =
  16. 16.297 + 89 =
  17. 17.415 + 87 =
  18. 18.183 + 37 =
  19. 19.47 + 98 =
  20. 20.451 + 27 =
  21. 21.329 + 88 =
  22. 22.150 + 58 =
  23. 23.297 + 68 =
  24. 24.167 + 17 =
  25. 25.490 + 49 =
  26. 26.71 + 29 =
  27. 27.148 + 39 =
  28. 28.396 + 28 =
  29. 29.32 + 97 =
  30. 30.230 + 68 =
  31. 31.245 + 57 =
  32. 32.129 + 17 =
  33. 33.359 + 39 =
  34. 34.330 + 58 =
  35. 35.198 + 29 =
  36. 36.435 + 28 =
  37. 37.424 + 88 =
  38. 38.471 + 49 =
  39. 39.122 + 48 =
  40. 40.150 + 87 =

Answer key

  1. 551
  2. 349
  3. 104
  4. 281
  5. 407
  6. 407
  7. 154
  8. 279
  9. 117
  10. 224
  11. 337
  12. 213
  13. 490
  14. 283
  15. 208
  16. 386
  17. 502
  18. 220
  19. 145
  20. 478
  21. 417
  22. 208
  23. 365
  24. 184
  25. 539
  26. 100
  27. 187
  28. 424
  29. 129
  30. 298
  31. 302
  32. 146
  33. 398
  34. 388
  35. 227
  36. 463
  37. 512
  38. 520
  39. 170
  40. 237

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