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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 40 · 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. 1.91 + 38 =
  2. 2.263 + 49 =
  3. 3.326 + 79 =
  4. 4.215 + 37 =
  5. 5.95 + 99 =
  6. 6.499 + 97 =
  7. 7.236 + 27 =
  8. 8.266 + 98 =
  9. 9.373 + 78 =
  10. 10.367 + 27 =
  11. 11.324 + 78 =
  12. 12.458 + 29 =
  13. 13.255 + 38 =
  14. 14.112 + 29 =
  15. 15.149 + 19 =
  16. 16.134 + 37 =
  17. 17.147 + 58 =
  18. 18.344 + 88 =
  19. 19.337 + 87 =
  20. 20.84 + 68 =
  21. 21.227 + 98 =
  22. 22.389 + 19 =
  23. 23.117 + 18 =
  24. 24.239 + 38 =
  25. 25.493 + 78 =
  26. 26.63 + 78 =
  27. 27.314 + 59 =
  28. 28.298 + 78 =
  29. 29.266 + 48 =
  30. 30.173 + 77 =
  31. 31.171 + 47 =
  32. 32.484 + 49 =
  33. 33.274 + 87 =
  34. 34.88 + 88 =
  35. 35.113 + 19 =
  36. 36.346 + 98 =
  37. 37.434 + 17 =
  38. 38.236 + 67 =
  39. 39.401 + 67 =
  40. 40.82 + 97 =

Answer key

  1. 129
  2. 312
  3. 405
  4. 252
  5. 194
  6. 596
  7. 263
  8. 364
  9. 451
  10. 394
  11. 402
  12. 487
  13. 293
  14. 141
  15. 168
  16. 171
  17. 205
  18. 432
  19. 424
  20. 152
  21. 325
  22. 408
  23. 135
  24. 277
  25. 571
  26. 141
  27. 373
  28. 376
  29. 314
  30. 250
  31. 218
  32. 533
  33. 361
  34. 176
  35. 132
  36. 444
  37. 451
  38. 303
  39. 468
  40. 179

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