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Why does multiplication precede addition?

  1. Dec 27, 2007 #1
    We all know BEDMAS from grade school: brackets, exponents, division, multiplication, addition, subtraction. My question is, why does multiplication precede addition, and likewise their inverse operations?
  2. jcsd
  3. Dec 27, 2007 #2


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    So you would suggest that we make the multiplication before addition, and the inverses of these behind each operation respectively?

    How would you pronounce BEASMD?
  4. Dec 27, 2007 #3
    Thats what we already have, multiplication before addition. I'm not proposing anything, I'm just curious as to why it was decided to be that way.
  5. Dec 27, 2007 #4


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    It purely convention - useful to the reduce work one has to put in the make any expression have only one interpretation.

    Further, I'd rather have things this way. I think it's handier to deal with sums of products than products of sums. The latter are rarer (except in some trivial sense); they mean an expression is factorizable into smaller parts.
    Last edited: Dec 27, 2007
  6. Aug 9, 2010 #5
    Re: Bedmas

    just wondering if you say thats convection, then how come if you dont do BEDMAS properly you do not get the right answer?.
  7. Aug 9, 2010 #6


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    Re: Bedmas

    He said "convention", not "convection".

    And you would get the wrong answer because you would be doing the wrong thing!

    That's what "convention" means. If some one asked you what 3+ 4 was and you answered "12" because you thought "+" meant multiplication, you would have given the wrong answer because you were wrong about the convention that "+" means addition, not multiplication.
  8. Aug 9, 2010 #7
    Re: Bedmas

    Anyway, BEDMAS is the same as BEDMSA! But it doesn't sound good...
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