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Math Help - A difficult puzzle

  1. #1
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    A difficult puzzle

    between the numbers 1,2,3,4,5,6,7,8,9 put that sign you want and add them in order to give sum 10!
    (Each number put only once, and only + ,- .. not *,/)
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  2. #2
    MHF Contributor
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    Can't be done....unless I'm missing something (still on 1st coffee!)

    Sum of the 9 digits = 45;
    a + b = 45
    a - b = 10
    ========
    2a = 55
    a = 27.5

    Are we allowed to use the likes of 1+23?

    1 to 8 works; sum = 36:
    a + b = 36
    a - b = 10
    ========
    2a = 46
    a = 23
    So 23 and -13:
    1 + 2 + 3 + 4 + 5 - 6 - 7 + 8 = 10
    1 + 2 + 3 + 4 - 5 + 6 + 7 - 8 = 10 ....and a few others...
    Last edited by Wilmer; January 19th 2011 at 09:37 AM.
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