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Simple maths question

  1. Feb 28, 2012 #1
    Okay I saw this on Facebook not long ago and I'm just confused with a really simple question.

    The question is basically
    6/2(1+2)

    Now using my head I get 9, using wolfram alpha I get 9 and also Google gives me 9.

    But then I place this into all 3 of my calculators I get the answer of 1.
    I'm assuming this is because it does the 2(1+2) part first and then divides 6/6 to get 1.
    And I also placed brackets around it to get (6/2)(1+2) which gets me the answer of 9 (thus assuming that it does do it that way).

    But shouldn't the order of operations go from left to right? in terms of the multiplication and division?? Am I looking at this wrong?
     
  2. jcsd
  3. Feb 28, 2012 #2
    Read the sticky at the top of the general math forum.
     
  4. Feb 28, 2012 #3

    chiro

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    Hey trustnoone and welcome to the forums.

    In short the answer is BODMAS (Brackets Division Multiplication Addition Subtraction)

    Basically evaluate all the bracketed terms first and then use the DMAS rules.

    Inner brackets get evaluated before outer brackets, but in the end once you evaluate the brackets then you just evaluate the expression using the DMAS ordering.

    It doesn't fail and its easy to remember :)

    Also if you use things other than arithmetic (like exponentiation) then you need to adjust for that as well.
     
  5. Feb 28, 2012 #4

    micromass

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