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Homework Help: Base 5 problem.

  1. Jan 18, 2010 #1
    1. The problem statement, all variables and given/known data

    The number 4312 in base ten is (4*10^3) + (3*10^2) + (1*10^1) + (2*10^0)

    4312 in base six is (4*6^3) + (3*6^2) + (1*6^1) + (2*6^0) which is 980

    therefore 4312 in base six is equal to 980 in base 10


    a) does 124 in base 5 represent an odd number?

    b) how can you tell if a number is odd in base 10 by looking t its base 5 representation

    2. Relevant equations

    3. The attempt at a solution

    i figured out that 124 in base five is 39 in base 10 and that means the answer to question a) is yes.

    But i have no idea how to answer question b).
  2. jcsd
  3. Jan 18, 2010 #2
    i have a guess.

    If you add the digits together and it is an odd number, then that number in base five is odd when turned into base ten.

    for instance, 124 = 1+2+4 = 7, which is odd, so when you make 124 base 5 into base 10 it must be odd.

    please tell me if that is incorrect.
  4. Jan 19, 2010 #3


    User Avatar
    Gold Member

    Yes. You are correct.
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