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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 814 · 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. 1.78 + 78 =
  2. 2.455 + 88 =
  3. 3.226 + 59 =
  4. 4.310 + 58 =
  5. 5.60 + 37 =
  6. 6.32 + 38 =
  7. 7.261 + 68 =
  8. 8.154 + 18 =
  9. 9.464 + 47 =
  10. 10.371 + 38 =
  11. 11.424 + 97 =
  12. 12.408 + 87 =
  13. 13.297 + 67 =
  14. 14.249 + 29 =
  15. 15.290 + 38 =
  16. 16.243 + 47 =
  17. 17.141 + 48 =
  18. 18.423 + 38 =
  19. 19.97 + 58 =
  20. 20.476 + 47 =
  21. 21.162 + 97 =
  22. 22.99 + 18 =
  23. 23.31 + 39 =
  24. 24.222 + 57 =
  25. 25.119 + 28 =
  26. 26.411 + 47 =
  27. 27.296 + 37 =
  28. 28.410 + 19 =
  29. 29.434 + 18 =
  30. 30.390 + 18 =
  31. 31.162 + 78 =
  32. 32.383 + 17 =
  33. 33.292 + 99 =
  34. 34.336 + 27 =
  35. 35.62 + 89 =
  36. 36.272 + 77 =
  37. 37.175 + 39 =
  38. 38.388 + 58 =
  39. 39.47 + 17 =
  40. 40.137 + 88 =

Answer key

  1. 156
  2. 543
  3. 285
  4. 368
  5. 97
  6. 70
  7. 329
  8. 172
  9. 511
  10. 409
  11. 521
  12. 495
  13. 364
  14. 278
  15. 328
  16. 290
  17. 189
  18. 461
  19. 155
  20. 523
  21. 259
  22. 117
  23. 70
  24. 279
  25. 147
  26. 458
  27. 333
  28. 429
  29. 452
  30. 408
  31. 240
  32. 400
  33. 391
  34. 363
  35. 151
  36. 349
  37. 214
  38. 446
  39. 64
  40. 225

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