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ROunding When Eactly 5

  1. May 27, 2013 #1
    1. The problem statement, all variables and given/known data
    I'm very confused as to when your supposed to add up or down when a number follows a five.

    2. Relevant equations

    3. The attempt at a solution
    For instance, round 5.65 to 1 decimal. THe answer is 5.6, isn't this because when an even number is followed by a five you round down?

    However, I was always told that 5.65 rounded to 1 decimal place is simply 5.7
  2. jcsd
  3. May 27, 2013 #2


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    Usually, 5 is rounded up.
    In computer science, "round down everything (including .9)" is common, and "round .5 to the nearest even number" is used, too (this can reduce rounding errors later).
  4. May 27, 2013 #3


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    I've always rounded up when the last digit is 5-9. Thus 5.65 = 5.7. In my experience, this is customary unless a special rule is imposed for a certain situation.

    There is a lengthy article here about different types of rounding:
  5. May 28, 2013 #4
    I've always done rounding 5 to the even number. Reasoning being that over the course of multiple rounding events you will round some up and some down thereby minimizing the skew to either direction.
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