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Math problem, but I think it is more appropriate here

  1. Dec 16, 2016 #1

    Averagesupernova

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    Gold Member

    This problem is floating around the web:
    6 / 2(1+2)
    A disappointing number of replies say the answer is 9. Where I come from the answer is 1. Now I will be the first to admit that I maybe I am wrong. But what is disheartening is the number of people that are on each side of the fence. If one out of 10 said the answer was 1 I would question my own answer more than I have. Or, conversely if one out of 10 said the answer was 9. But no matter how you slice it there are enough people with wrong answers out there that it really disappoints me.
     
  2. jcsd
  3. Dec 16, 2016 #2

    EnumaElish

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    Logically it's 9. Typographically it may be 1. If I thought "/" means "times seven" then it'd be 1,764 I think.
     
  4. Dec 16, 2016 #3
  5. Dec 16, 2016 #4

    Averagesupernova

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    The way I see it is if you replace the 2 inside the parenthesis with an X and assign either 1 or 9 to the other side of the equation and solve what will X be? This would be a pretty basic algebra problem that everyone would agree on. Yet when it is presented as I showed in the first post it is unacceptable?
    -
    If a mod thinks this should be moved I would have no problem with it.
     
  6. Dec 16, 2016 #5

    Mark44

    Staff: Mentor

    There is no "other side to the equation." What you wrote is an expression, not an equation. An equation always has = in it.


    With or without x, the expression is still ambiguous.
     
  7. Dec 16, 2016 #6
    I think part of what makes this and other problems look ambiguous is the single line notation we resort to when using text only as a means of writing. Now watch me be Mr. Fancypants and use LaTex:

    ## \frac{6}{2(1+2)} ##

    ooh now it's pretty. It's also a lot less confusing, and I imagine that semi-numerate people would get the same answer if it were written that way. In fact when it's written like this I'd probably cancel the 2, turn the 6 into a 3, then I'd have ## \frac{3}{3} ## which is easier for me.

    (Of course, this is looking elementary now, but with bigger numbers especially you could see the advantage).

    -Dave K
     
  8. Dec 16, 2016 #7

    Mark44

    Staff: Mentor

    If it is written as ##\frac 6 {2(1 + 2)}## then I would agree that this simplifies to 1.

    As written, though, most would say that this simplifies to 9, according to the usual rules of precedence.
     
  9. Dec 16, 2016 #8

    Mark44

    Staff: Mentor

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