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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 142 · 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. 1.75 + 49 =
  2. 2.242 + 57 =
  3. 3.496 + 19 =
  4. 4.344 + 19 =
  5. 5.83 + 58 =
  6. 6.457 + 18 =
  7. 7.292 + 47 =
  8. 8.200 + 18 =
  9. 9.492 + 28 =
  10. 10.163 + 69 =
  11. 11.327 + 79 =
  12. 12.203 + 87 =
  13. 13.87 + 59 =
  14. 14.407 + 99 =
  15. 15.428 + 89 =
  16. 16.279 + 17 =
  17. 17.383 + 19 =
  18. 18.386 + 59 =
  19. 19.180 + 87 =
  20. 20.177 + 77 =
  21. 21.147 + 28 =
  22. 22.274 + 57 =
  23. 23.315 + 17 =
  24. 24.46 + 27 =
  25. 25.180 + 77 =
  26. 26.219 + 28 =
  27. 27.131 + 47 =
  28. 28.139 + 78 =
  29. 29.344 + 19 =
  30. 30.276 + 57 =
  31. 31.71 + 49 =
  32. 32.438 + 49 =
  33. 33.60 + 49 =
  34. 34.410 + 77 =
  35. 35.133 + 29 =
  36. 36.200 + 48 =
  37. 37.474 + 19 =
  38. 38.287 + 97 =
  39. 39.389 + 59 =
  40. 40.378 + 49 =

Answer key

  1. 124
  2. 299
  3. 515
  4. 363
  5. 141
  6. 475
  7. 339
  8. 218
  9. 520
  10. 232
  11. 406
  12. 290
  13. 146
  14. 506
  15. 517
  16. 296
  17. 402
  18. 445
  19. 267
  20. 254
  21. 175
  22. 331
  23. 332
  24. 73
  25. 257
  26. 247
  27. 178
  28. 217
  29. 363
  30. 333
  31. 120
  32. 487
  33. 109
  34. 487
  35. 162
  36. 248
  37. 493
  38. 384
  39. 448
  40. 427

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