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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 447 · 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. 1.233 + 29 =
  2. 2.409 + 18 =
  3. 3.363 + 49 =
  4. 4.324 + 89 =
  5. 5.236 + 57 =
  6. 6.446 + 47 =
  7. 7.212 + 28 =
  8. 8.158 + 27 =
  9. 9.471 + 17 =
  10. 10.431 + 47 =
  11. 11.314 + 89 =
  12. 12.486 + 37 =
  13. 13.193 + 78 =
  14. 14.393 + 69 =
  15. 15.336 + 37 =
  16. 16.358 + 18 =
  17. 17.322 + 47 =
  18. 18.135 + 57 =
  19. 19.130 + 17 =
  20. 20.207 + 67 =
  21. 21.260 + 68 =
  22. 22.247 + 78 =
  23. 23.361 + 27 =
  24. 24.62 + 27 =
  25. 25.322 + 68 =
  26. 26.257 + 27 =
  27. 27.298 + 39 =
  28. 28.156 + 97 =
  29. 29.453 + 68 =
  30. 30.230 + 38 =
  31. 31.289 + 57 =
  32. 32.348 + 29 =
  33. 33.492 + 97 =
  34. 34.308 + 27 =
  35. 35.174 + 39 =
  36. 36.85 + 57 =
  37. 37.139 + 58 =
  38. 38.184 + 39 =
  39. 39.191 + 57 =
  40. 40.328 + 99 =

Answer key

  1. 262
  2. 427
  3. 412
  4. 413
  5. 293
  6. 493
  7. 240
  8. 185
  9. 488
  10. 478
  11. 403
  12. 523
  13. 271
  14. 462
  15. 373
  16. 376
  17. 369
  18. 192
  19. 147
  20. 274
  21. 328
  22. 325
  23. 388
  24. 89
  25. 390
  26. 284
  27. 337
  28. 253
  29. 521
  30. 268
  31. 346
  32. 377
  33. 589
  34. 335
  35. 213
  36. 142
  37. 197
  38. 223
  39. 248
  40. 427

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