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Math Help - Basic order of operation question

  1. #1
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    Basic order of operation question

    Ok so this is pretty basic:

    -8-5(-8+4)
    = 12

    so you do (-8+4) = -4

    then you multiply the brackets, but heres where im confused, why do you 5* -4 =-20 and not -5*-20, because it is a negative 5 before the brackets right?
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  2. #2
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    Re: Basic order of operation question

    Quote Originally Posted by ollyrutts View Post
    Ok so this is pretty basic:

    -8-5(-8+4)
    = 12

    so you do (-8+4) = -4

    then you multiply the brackets, but heres where im confused, why do you 5* -4 =-20 and not -5*-20, because it is a negative 5 before the brackets right?
    Hi Ollyruts,

    Yes, this is pretty basic. Here are the steps with the order of operations:

    [1.] -8 - 5(-8 + 4)

    [2.] -8 -5(-4)

    [3.] -8 + 20

    [4.] 12
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  3. #3
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    Re: Basic order of operation question

    So can you do it two ways i.e.

    -5(-4) = 20
    = -8 + 20
    =12

    or

    5(-4) = -20
    -8 - -20
    12

    is this ok to do?
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  4. #4
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    Re: Basic order of operation question

    Yes, although the "- -" without parentheses looks strange! Slightly clearer would be -8- (-20)= -8+ 20.
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