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Math Help - Fration help

  1. #1
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    Fration help

    I hoping somone will help me understand why I'm getting the wrong answer to this problem

    Negetive sixty five sevenths divided by thirteen.
    -65/7 \13
    My answer is -65/91 Negetive sixty five ninety ones.
    Last edited by Gerry; October 12th 2007 at 12:04 PM.
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  2. #2
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    Quote Originally Posted by Gerry View Post
    I hoping somone will help me understand why I'm getting the wrong answer to this problem

    Negetive sixty five sevenths divided by thirteen.
    -65/7 \13
    My answer is -67/91 Negetive sixty seven ninety ones.
    Hello,

    you are supposed to know that every (integer) number can be written as a fraction: 13 = \frac{13}{1}

    With this property your division becomes:

    -\frac{65}{7} \div 13 = -\frac{\frac{65}{7}}{\frac{13}{1}} = -\frac{\not{6}\not{5}^5}{7} \cdot \frac{1}{\not{1}\not{3}_1} = -\frac57
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  3. #3
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    canceling

    My problem is the canceling I guess.

    I knew to take the recipricole of 13 and change the operation to Multiplication. Then I just thought you multiply the Numerators and Denominators across.

    when you have the problem set up as:

    65/7 x 1/13 =

    are you supposed to cross divide?

    thanx for your help.
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  4. #4
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    Quote Originally Posted by Gerry View Post
    My problem is the canceling I guess.

    I knew to take the recipricole of 13 and change the operation to Multiplication. Then I just thought you multiply the Numerators and Denominators across.

    when you have the problem set up as:

    65/7 x 1/13 =

    are you supposed to cross divide?

    thanx for your help.
    "Cross divide?" Never heard of it. But perhaps doing it in this format will help:
    \frac{65}{7} \times \frac{1}{13} = \frac{65}{7 \cdot 13}

    = \frac{5 \cdot 13}{7 \cdot 13} = \frac{5}{7}

    -Dan
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  5. #5
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    Hello, Gerry!

    Don't kick yourself too hard . . .


    Negetive sixty five sevenths divided by thirteen.
    -65/7 \13
    My answer is -67/91
    Negetive sixty seven ninety ones.

    You meant sixty-five, did you?

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  6. #6
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    Doh!!!

    Yes... in fact I caught that and changed it.. Hehehe...
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