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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 478 · 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. 1.416 + 39 =
  2. 2.352 + 28 =
  3. 3.68 + 17 =
  4. 4.376 + 97 =
  5. 5.322 + 67 =
  6. 6.353 + 38 =
  7. 7.201 + 67 =
  8. 8.239 + 79 =
  9. 9.46 + 29 =
  10. 10.342 + 28 =
  11. 11.29 + 77 =
  12. 12.360 + 48 =
  13. 13.93 + 48 =
  14. 14.240 + 57 =
  15. 15.287 + 87 =
  16. 16.261 + 28 =
  17. 17.405 + 58 =
  18. 18.337 + 78 =
  19. 19.61 + 59 =
  20. 20.301 + 77 =
  21. 21.409 + 69 =
  22. 22.76 + 29 =
  23. 23.449 + 67 =
  24. 24.373 + 88 =
  25. 25.420 + 98 =
  26. 26.57 + 97 =
  27. 27.448 + 28 =
  28. 28.239 + 17 =
  29. 29.42 + 68 =
  30. 30.308 + 27 =
  31. 31.111 + 47 =
  32. 32.92 + 98 =
  33. 33.457 + 98 =
  34. 34.359 + 77 =
  35. 35.97 + 88 =
  36. 36.492 + 29 =
  37. 37.55 + 59 =
  38. 38.299 + 59 =
  39. 39.279 + 49 =
  40. 40.224 + 48 =

Answer key

  1. 455
  2. 380
  3. 85
  4. 473
  5. 389
  6. 391
  7. 268
  8. 318
  9. 75
  10. 370
  11. 106
  12. 408
  13. 141
  14. 297
  15. 374
  16. 289
  17. 463
  18. 415
  19. 120
  20. 378
  21. 478
  22. 105
  23. 516
  24. 461
  25. 518
  26. 154
  27. 476
  28. 256
  29. 110
  30. 335
  31. 158
  32. 190
  33. 555
  34. 436
  35. 185
  36. 521
  37. 114
  38. 358
  39. 328
  40. 272

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