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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 427 · 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. 1.321 + 48 =
  2. 2.162 + 87 =
  3. 3.255 + 78 =
  4. 4.106 + 49 =
  5. 5.358 + 97 =
  6. 6.198 + 78 =
  7. 7.83 + 19 =
  8. 8.410 + 99 =
  9. 9.443 + 39 =
  10. 10.131 + 17 =
  11. 11.231 + 19 =
  12. 12.240 + 27 =
  13. 13.113 + 49 =
  14. 14.64 + 28 =
  15. 15.486 + 68 =
  16. 16.197 + 27 =
  17. 17.449 + 37 =
  18. 18.427 + 77 =
  19. 19.96 + 57 =
  20. 20.339 + 79 =
  21. 21.147 + 19 =
  22. 22.406 + 27 =
  23. 23.474 + 97 =
  24. 24.381 + 68 =
  25. 25.125 + 58 =
  26. 26.66 + 89 =
  27. 27.216 + 27 =
  28. 28.149 + 27 =
  29. 29.262 + 67 =
  30. 30.243 + 58 =
  31. 31.282 + 78 =
  32. 32.51 + 78 =
  33. 33.486 + 87 =
  34. 34.157 + 37 =
  35. 35.307 + 17 =
  36. 36.111 + 68 =
  37. 37.303 + 37 =
  38. 38.468 + 17 =
  39. 39.104 + 58 =
  40. 40.421 + 88 =

Answer key

  1. 369
  2. 249
  3. 333
  4. 155
  5. 455
  6. 276
  7. 102
  8. 509
  9. 482
  10. 148
  11. 250
  12. 267
  13. 162
  14. 92
  15. 554
  16. 224
  17. 486
  18. 504
  19. 153
  20. 418
  21. 166
  22. 433
  23. 571
  24. 449
  25. 183
  26. 155
  27. 243
  28. 176
  29. 329
  30. 301
  31. 360
  32. 129
  33. 573
  34. 194
  35. 324
  36. 179
  37. 340
  38. 485
  39. 162
  40. 509

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