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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 359 · 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. 1.51 + 88 =
  2. 2.323 + 39 =
  3. 3.339 + 37 =
  4. 4.348 + 39 =
  5. 5.156 + 88 =
  6. 6.461 + 39 =
  7. 7.341 + 98 =
  8. 8.281 + 59 =
  9. 9.212 + 59 =
  10. 10.35 + 68 =
  11. 11.342 + 19 =
  12. 12.481 + 99 =
  13. 13.239 + 28 =
  14. 14.84 + 89 =
  15. 15.151 + 69 =
  16. 16.114 + 37 =
  17. 17.105 + 29 =
  18. 18.129 + 29 =
  19. 19.468 + 49 =
  20. 20.125 + 17 =
  21. 21.43 + 69 =
  22. 22.87 + 98 =
  23. 23.143 + 89 =
  24. 24.29 + 28 =
  25. 25.226 + 97 =
  26. 26.410 + 57 =
  27. 27.293 + 29 =
  28. 28.407 + 98 =
  29. 29.68 + 17 =
  30. 30.329 + 97 =
  31. 31.221 + 29 =
  32. 32.408 + 79 =
  33. 33.369 + 88 =
  34. 34.297 + 87 =
  35. 35.121 + 38 =
  36. 36.346 + 38 =
  37. 37.224 + 47 =
  38. 38.186 + 57 =
  39. 39.129 + 18 =
  40. 40.30 + 87 =

Answer key

  1. 139
  2. 362
  3. 376
  4. 387
  5. 244
  6. 500
  7. 439
  8. 340
  9. 271
  10. 103
  11. 361
  12. 580
  13. 267
  14. 173
  15. 220
  16. 151
  17. 134
  18. 158
  19. 517
  20. 142
  21. 112
  22. 185
  23. 232
  24. 57
  25. 323
  26. 467
  27. 322
  28. 505
  29. 85
  30. 426
  31. 250
  32. 487
  33. 457
  34. 384
  35. 159
  36. 384
  37. 271
  38. 243
  39. 147
  40. 117

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