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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 303 · 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. 1.422 + 49 =
  2. 2.461 + 28 =
  3. 3.71 + 18 =
  4. 4.111 + 39 =
  5. 5.93 + 58 =
  6. 6.88 + 57 =
  7. 7.105 + 97 =
  8. 8.64 + 19 =
  9. 9.218 + 37 =
  10. 10.166 + 38 =
  11. 11.178 + 59 =
  12. 12.339 + 48 =
  13. 13.463 + 48 =
  14. 14.458 + 49 =
  15. 15.492 + 37 =
  16. 16.461 + 38 =
  17. 17.277 + 27 =
  18. 18.69 + 39 =
  19. 19.192 + 18 =
  20. 20.135 + 89 =
  21. 21.393 + 39 =
  22. 22.235 + 69 =
  23. 23.442 + 78 =
  24. 24.161 + 69 =
  25. 25.323 + 29 =
  26. 26.335 + 87 =
  27. 27.164 + 48 =
  28. 28.181 + 57 =
  29. 29.275 + 78 =
  30. 30.307 + 28 =
  31. 31.80 + 37 =
  32. 32.158 + 99 =
  33. 33.299 + 49 =
  34. 34.244 + 77 =
  35. 35.67 + 77 =
  36. 36.78 + 87 =
  37. 37.41 + 37 =
  38. 38.49 + 57 =
  39. 39.287 + 78 =
  40. 40.190 + 39 =

Answer key

  1. 471
  2. 489
  3. 89
  4. 150
  5. 151
  6. 145
  7. 202
  8. 83
  9. 255
  10. 204
  11. 237
  12. 387
  13. 511
  14. 507
  15. 529
  16. 499
  17. 304
  18. 108
  19. 210
  20. 224
  21. 432
  22. 304
  23. 520
  24. 230
  25. 352
  26. 422
  27. 212
  28. 238
  29. 353
  30. 335
  31. 117
  32. 257
  33. 348
  34. 321
  35. 144
  36. 165
  37. 78
  38. 106
  39. 365
  40. 229

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