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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 70 · 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. 1.460 + 38 =
  2. 2.437 + 87 =
  3. 3.245 + 57 =
  4. 4.98 + 29 =
  5. 5.464 + 48 =
  6. 6.183 + 99 =
  7. 7.368 + 48 =
  8. 8.120 + 57 =
  9. 9.289 + 48 =
  10. 10.475 + 48 =
  11. 11.318 + 38 =
  12. 12.126 + 79 =
  13. 13.74 + 27 =
  14. 14.27 + 97 =
  15. 15.405 + 39 =
  16. 16.244 + 89 =
  17. 17.427 + 89 =
  18. 18.378 + 17 =
  19. 19.343 + 97 =
  20. 20.436 + 47 =
  21. 21.499 + 38 =
  22. 22.176 + 29 =
  23. 23.335 + 97 =
  24. 24.39 + 47 =
  25. 25.37 + 69 =
  26. 26.413 + 38 =
  27. 27.119 + 78 =
  28. 28.173 + 89 =
  29. 29.424 + 97 =
  30. 30.216 + 59 =
  31. 31.37 + 47 =
  32. 32.89 + 17 =
  33. 33.271 + 17 =
  34. 34.470 + 39 =
  35. 35.47 + 38 =
  36. 36.115 + 29 =
  37. 37.27 + 38 =
  38. 38.224 + 97 =
  39. 39.495 + 49 =
  40. 40.219 + 68 =

Answer key

  1. 498
  2. 524
  3. 302
  4. 127
  5. 512
  6. 282
  7. 416
  8. 177
  9. 337
  10. 523
  11. 356
  12. 205
  13. 101
  14. 124
  15. 444
  16. 333
  17. 516
  18. 395
  19. 440
  20. 483
  21. 537
  22. 205
  23. 432
  24. 86
  25. 106
  26. 451
  27. 197
  28. 262
  29. 521
  30. 275
  31. 84
  32. 106
  33. 288
  34. 509
  35. 85
  36. 144
  37. 65
  38. 321
  39. 544
  40. 287

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