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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 729 · 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. 1.459 + 89 =
  2. 2.253 + 99 =
  3. 3.81 + 57 =
  4. 4.127 + 98 =
  5. 5.482 + 28 =
  6. 6.273 + 28 =
  7. 7.282 + 39 =
  8. 8.313 + 19 =
  9. 9.476 + 58 =
  10. 10.255 + 17 =
  11. 11.173 + 97 =
  12. 12.172 + 58 =
  13. 13.397 + 57 =
  14. 14.279 + 17 =
  15. 15.308 + 17 =
  16. 16.166 + 27 =
  17. 17.338 + 87 =
  18. 18.483 + 88 =
  19. 19.31 + 69 =
  20. 20.156 + 59 =
  21. 21.319 + 79 =
  22. 22.439 + 37 =
  23. 23.123 + 19 =
  24. 24.280 + 28 =
  25. 25.414 + 78 =
  26. 26.342 + 99 =
  27. 27.250 + 29 =
  28. 28.493 + 27 =
  29. 29.453 + 48 =
  30. 30.428 + 19 =
  31. 31.443 + 79 =
  32. 32.270 + 58 =
  33. 33.75 + 27 =
  34. 34.45 + 67 =
  35. 35.80 + 19 =
  36. 36.360 + 19 =
  37. 37.266 + 17 =
  38. 38.79 + 68 =
  39. 39.135 + 57 =
  40. 40.291 + 78 =

Answer key

  1. 548
  2. 352
  3. 138
  4. 225
  5. 510
  6. 301
  7. 321
  8. 332
  9. 534
  10. 272
  11. 270
  12. 230
  13. 454
  14. 296
  15. 325
  16. 193
  17. 425
  18. 571
  19. 100
  20. 215
  21. 398
  22. 476
  23. 142
  24. 308
  25. 492
  26. 441
  27. 279
  28. 520
  29. 501
  30. 447
  31. 522
  32. 328
  33. 102
  34. 112
  35. 99
  36. 379
  37. 283
  38. 147
  39. 192
  40. 369

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