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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 177 · 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. 1.395 + 39 =
  2. 2.311 + 38 =
  3. 3.139 + 47 =
  4. 4.457 + 68 =
  5. 5.329 + 28 =
  6. 6.346 + 18 =
  7. 7.98 + 39 =
  8. 8.161 + 99 =
  9. 9.98 + 77 =
  10. 10.469 + 78 =
  11. 11.105 + 19 =
  12. 12.408 + 28 =
  13. 13.97 + 28 =
  14. 14.312 + 57 =
  15. 15.386 + 47 =
  16. 16.78 + 87 =
  17. 17.269 + 77 =
  18. 18.131 + 19 =
  19. 19.188 + 59 =
  20. 20.204 + 27 =
  21. 21.304 + 98 =
  22. 22.290 + 17 =
  23. 23.466 + 29 =
  24. 24.419 + 79 =
  25. 25.162 + 48 =
  26. 26.130 + 79 =
  27. 27.471 + 18 =
  28. 28.51 + 27 =
  29. 29.162 + 67 =
  30. 30.399 + 68 =
  31. 31.93 + 29 =
  32. 32.386 + 87 =
  33. 33.74 + 27 =
  34. 34.214 + 87 =
  35. 35.82 + 37 =
  36. 36.460 + 18 =
  37. 37.160 + 97 =
  38. 38.155 + 69 =
  39. 39.363 + 87 =
  40. 40.357 + 18 =

Answer key

  1. 434
  2. 349
  3. 186
  4. 525
  5. 357
  6. 364
  7. 137
  8. 260
  9. 175
  10. 547
  11. 124
  12. 436
  13. 125
  14. 369
  15. 433
  16. 165
  17. 346
  18. 150
  19. 247
  20. 231
  21. 402
  22. 307
  23. 495
  24. 498
  25. 210
  26. 209
  27. 489
  28. 78
  29. 229
  30. 467
  31. 122
  32. 473
  33. 101
  34. 301
  35. 119
  36. 478
  37. 257
  38. 224
  39. 450
  40. 375

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