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Math Help - simplifying

  1. #1
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    simplifying

    i need to know what this would be when simplified also i need to know how you did it thanks

    21
    ---
    35
    Last edited by andyboy179; April 28th 2009 at 06:34 AM. Reason: spelling mistake
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  2. #2
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    Talking

    To learn how to simplify fractions, try here.
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  3. #3
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    i know how to do questions like these im just stuck on this 1 i wanna also know if the answer will be just be

    21
    ---
    35
    or if it will be something like 10.5
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  4. #4
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    Quote Originally Posted by andyboy179 View Post
    i know how to do questions like these im just stuck on this 1 i wanna also know if the answer will be just be

    21
    ---
    35
    or if it will be something like 10.5
    You have to examine the numerator and the denominator if they contain a common factor. With your example you get:

    \dfrac{21}{35} = \dfrac{7 \cdot 3}{7 \cdot 5} = \dfrac11 \cdot \dfrac35 = \dfrac35
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  5. #5
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    Quote Originally Posted by earboth View Post
    You have to examine the numerator and the denominator if they contain a common factor. With your example you get:

    \dfrac{21}{35} = \dfrac{7 \cdot 3}{7 \cdot 5} = \dfrac11 \cdot \dfrac35 = \dfrac35

    what did u do to get 7.3 and 7.5
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  6. #6
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    Quote Originally Posted by andyboy179 View Post
    what did u do to get 7.3 and 7.5
    I assume that you have heard about prime decomposition (?): Each natural number can be written as a product of prime factors OR (if the number is a prime factor itself) as 1 \cdot number.

    The first prime numbers (which you should learn by heart) are: 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, ...

    There are an infinite number of prime numbers.

    I examined 21: It is divisible by 3 that means 3 must be a factor in 21. The remainder is 7 which is a prime factor too. Thus 21 = 3 \cdot 7

    Do the same with 35.
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  7. #7
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    This seems way to obvious so it is probably wrong but..
    Both 21 and 35 can be divided by 7.

    21/7 = 3
    35/7 = 5

    So it simplified would just be \dfrac{3}{5}?
    Last edited by Kyle_F107; April 30th 2009 at 08:07 AM. Reason: Bad grammer :)
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