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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 640 · 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. 1.110 + 48 =
  2. 2.362 + 98 =
  3. 3.93 + 79 =
  4. 4.29 + 19 =
  5. 5.353 + 18 =
  6. 6.41 + 97 =
  7. 7.368 + 28 =
  8. 8.446 + 47 =
  9. 9.31 + 69 =
  10. 10.191 + 27 =
  11. 11.381 + 29 =
  12. 12.254 + 27 =
  13. 13.474 + 28 =
  14. 14.423 + 88 =
  15. 15.475 + 48 =
  16. 16.33 + 18 =
  17. 17.398 + 59 =
  18. 18.30 + 97 =
  19. 19.51 + 97 =
  20. 20.315 + 18 =
  21. 21.35 + 39 =
  22. 22.145 + 38 =
  23. 23.28 + 68 =
  24. 24.362 + 17 =
  25. 25.400 + 78 =
  26. 26.154 + 59 =
  27. 27.268 + 88 =
  28. 28.106 + 17 =
  29. 29.420 + 28 =
  30. 30.190 + 19 =
  31. 31.186 + 17 =
  32. 32.145 + 47 =
  33. 33.131 + 57 =
  34. 34.382 + 17 =
  35. 35.210 + 79 =
  36. 36.104 + 29 =
  37. 37.43 + 49 =
  38. 38.196 + 19 =
  39. 39.97 + 97 =
  40. 40.120 + 49 =

Answer key

  1. 158
  2. 460
  3. 172
  4. 48
  5. 371
  6. 138
  7. 396
  8. 493
  9. 100
  10. 218
  11. 410
  12. 281
  13. 502
  14. 511
  15. 523
  16. 51
  17. 457
  18. 127
  19. 148
  20. 333
  21. 74
  22. 183
  23. 96
  24. 379
  25. 478
  26. 213
  27. 356
  28. 123
  29. 448
  30. 209
  31. 203
  32. 192
  33. 188
  34. 399
  35. 289
  36. 133
  37. 92
  38. 215
  39. 194
  40. 169

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