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Math Help - pssh fractions n multiplying...

  1. #1
    Merlin_Hart
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    Wink pssh fractions n multiplying...

    kay well i need help cause i dont know how to do this
    13: 6 * 2/5
    14: 5 * 3/7
    15: 5 * 2/11
    16: 2 * 2/5
    17:2 1/2 * 3/4
    18: 2 1/4 * 3/5
    19: 1 1/2 * 3/7
    20: 1 1/3 * 4/5

    anyone care to like answere em or explain to me how to do this ? its confuzleses me reaaaaaaly bad.....
    Last edited by ThePerfectHacker; February 28th 2007 at 07:03 PM. Reason: needed more added
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  2. #2
    Super Member Aryth's Avatar
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    Well, when you multiply fractions, you treat the numerators (top number) and the denominators (bottom number) separately. And then put them back together as one whole fraction. Let's look at them:

    13. 6 * 2/5

    Can be rewritten as:

    6/1 *2/5

    We can separate the numerators:

    6 * 2 = 12 <--- That is our new numerator

    Same with our denominators:

    1 * 5 = 5 <--- That is our new denominator

    If we put those together, we get:

    12/5

    14. 5 * 3/7

    Using the same process:

    5/1 * 3/7

    5 * 3 = 15 <-- New numerator
    1 * 7 = 7 <-- New denominator

    Giving us:

    15/7

    15. 5 * 2/11

    5/1 * 2/11

    5 * 2 = 10
    1 * 11 = 11

    Giving us:

    10/11

    16. 2 * 2/5

    2/1 * 2/5

    2 * 2 = 4
    1 * 5 = 5

    Giving us:
    4/5

    17. For this one we must switch the mixed number 2 1/2 into an improper fraction, and how we do that is this:

    We take the denominator and multiply it by the whole number:

    2 * 2 = 4

    We then take that answer and add the numerator to it:

    4 + 1 = 5 <-- Our new numerator

    Making our fraction:

    5/2

    So our problem is rewritten like this:

    5/2 * 3/4

    We solve like normal:

    5 * 3 = 15
    2 * 4 = 8

    Giving us:

    15/8

    18. Same thing here:

    4 * 2 = 8

    8 + 1 = 9

    Giving us: 9/4

    9/4 * 3/5

    9 * 3 = 27
    4 * 5 = 20

    Giving us:
    27/20

    19. 1 1/2 = (2 * 1 + 1) /2 = 3/2

    3/2 * 3/7

    3 * 3 = 9
    2 * 7 = 14

    Giving us:
    9/14

    20. 1 1/3 = (3 * 1 + 1) /3 = 4/3

    4/3 * 4/5

    4 * 4 = 16
    3 * 5 = 15

    Giving us:
    16/15

    Thus your answers are:

    13. 12/5
    14. 15/7
    15. 10/11
    16. 4/5
    17. 15/8
    18. 27/20
    19. 19/4
    20. 16/15

    I hope that helped.
    Last edited by ThePerfectHacker; February 28th 2007 at 07:03 PM.
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