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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 721 · 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. 1.430 + 17 =
  2. 2.127 + 78 =
  3. 3.226 + 67 =
  4. 4.262 + 99 =
  5. 5.83 + 98 =
  6. 6.131 + 18 =
  7. 7.69 + 37 =
  8. 8.335 + 68 =
  9. 9.390 + 18 =
  10. 10.239 + 18 =
  11. 11.76 + 87 =
  12. 12.252 + 37 =
  13. 13.445 + 27 =
  14. 14.441 + 87 =
  15. 15.481 + 59 =
  16. 16.81 + 28 =
  17. 17.104 + 79 =
  18. 18.296 + 38 =
  19. 19.234 + 18 =
  20. 20.197 + 97 =
  21. 21.211 + 27 =
  22. 22.257 + 88 =
  23. 23.105 + 19 =
  24. 24.76 + 58 =
  25. 25.329 + 89 =
  26. 26.131 + 18 =
  27. 27.313 + 97 =
  28. 28.386 + 38 =
  29. 29.77 + 67 =
  30. 30.365 + 97 =
  31. 31.438 + 37 =
  32. 32.61 + 27 =
  33. 33.125 + 48 =
  34. 34.400 + 19 =
  35. 35.412 + 68 =
  36. 36.125 + 97 =
  37. 37.70 + 29 =
  38. 38.67 + 19 =
  39. 39.383 + 58 =
  40. 40.73 + 88 =

Answer key

  1. 447
  2. 205
  3. 293
  4. 361
  5. 181
  6. 149
  7. 106
  8. 403
  9. 408
  10. 257
  11. 163
  12. 289
  13. 472
  14. 528
  15. 540
  16. 109
  17. 183
  18. 334
  19. 252
  20. 294
  21. 238
  22. 345
  23. 124
  24. 134
  25. 418
  26. 149
  27. 410
  28. 424
  29. 144
  30. 462
  31. 475
  32. 88
  33. 173
  34. 419
  35. 480
  36. 222
  37. 99
  38. 86
  39. 441
  40. 161

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