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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 517 · 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. 1.81 + 28 =
  2. 2.488 + 97 =
  3. 3.80 + 27 =
  4. 4.407 + 17 =
  5. 5.33 + 67 =
  6. 6.410 + 48 =
  7. 7.369 + 77 =
  8. 8.465 + 28 =
  9. 9.218 + 47 =
  10. 10.252 + 19 =
  11. 11.427 + 78 =
  12. 12.350 + 99 =
  13. 13.260 + 48 =
  14. 14.470 + 57 =
  15. 15.413 + 97 =
  16. 16.298 + 79 =
  17. 17.313 + 67 =
  18. 18.160 + 99 =
  19. 19.284 + 67 =
  20. 20.460 + 99 =
  21. 21.460 + 19 =
  22. 22.326 + 18 =
  23. 23.33 + 68 =
  24. 24.69 + 79 =
  25. 25.484 + 49 =
  26. 26.123 + 27 =
  27. 27.89 + 68 =
  28. 28.469 + 37 =
  29. 29.296 + 19 =
  30. 30.29 + 29 =
  31. 31.321 + 98 =
  32. 32.78 + 19 =
  33. 33.215 + 49 =
  34. 34.223 + 29 =
  35. 35.331 + 38 =
  36. 36.112 + 58 =
  37. 37.104 + 79 =
  38. 38.384 + 57 =
  39. 39.259 + 88 =
  40. 40.46 + 28 =

Answer key

  1. 109
  2. 585
  3. 107
  4. 424
  5. 100
  6. 458
  7. 446
  8. 493
  9. 265
  10. 271
  11. 505
  12. 449
  13. 308
  14. 527
  15. 510
  16. 377
  17. 380
  18. 259
  19. 351
  20. 559
  21. 479
  22. 344
  23. 101
  24. 148
  25. 533
  26. 150
  27. 157
  28. 506
  29. 315
  30. 58
  31. 419
  32. 97
  33. 264
  34. 252
  35. 369
  36. 170
  37. 183
  38. 441
  39. 347
  40. 74

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