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    I know this is probably something really obvious I've missed here, but can anyone explain the workings of this? I've never come across it before and I can't find anywhere online that explains it.

    \frac{7}{5}+\frac{9}{6}+\frac{11  }{7}+\frac{13}{8}= \frac{1707}{280}

    Thanks.
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    (Original post by Srxjer)
    I know this is probably something really obvious I've missed here, but can anyone explain the workings of this? I've never come across it before and I can't find anywhere online that explains it.

    \frac{7}{5}+\frac{9}{6}+\frac{11  }{7}+\frac{13}{8}= \frac{1707}{280}

    Thanks.
    Just find the l.c.d?
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    1. You need to find the smallest number that the denominators all go in to, in this case it's 280. (Easiest way to do this I find is to multiply them all together, then try dividing by two and checking they all still go in).

    2.Whatever number you multiply the denominator by to get 280, you must multiply it's respective numerator by the same. eg. for 7/5, 5 x 56 = 280, so you multiply the 7 by 56 as well.

    3. You now have four numbers in the form x/280. Simply add these together normally.
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    (Original post by Srxjer)
    I know this is probably something really obvious I've missed here, but can anyone explain the workings of this? I've never come across it before and I can't find anywhere online that explains it.

    \frac{7}{5}+\frac{9}{6}+\frac{11  }{7}+\frac{13}{8}= \frac{1707}{280}

    Thanks.
    You're doing Further Maths?

    You should sue your GCSE Maths teacher, you may have made it, but think of all the poor souls that are suffering now!
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    (Original post by Kreuzuerk)
    Just find the l.c.d?
    (Original post by Potally_Tissed)
    1. You need to find the smallest number that the denominators all go in to, in this case it's 280. (Easiest way to do this I find is to multiply them all together, then try dividing by two and checking they all still go in).

    2.Whatever number you multiply the denominator by to get 280, you must multiply it's respective numerator by the same. eg. for 7/5, 5 x 56 = 280, so you multiply the 7 by 56 as well.

    3. You now have four numbers in the form x/280. Simply add these together normally.
    Yeah I tried that but 6 x 47 is 282. I wasn't to sure what to do with it.
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    (Original post by Srxjer)
    Yeah I tried that but 6 x 47 is 282. I wasn't to sure what to do with it.
    It isn't 47. 280/6 = 46.66666667. Did you notice that 9/6 is 1.5, or 420/280.
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    (Original post by hamzab)
    You're doing Further Maths?

    You should sue your GCSE Maths teacher, you may have made it, but think of all the poor souls that are suffering now!
    Yup. I definitely didn't do this in GCSE.
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    (Original post by Srxjer)
    Yup. I definitely didn't do this in GCSE.
    I should hope not. This would have been covered in primary school.
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    (Original post by Good bloke)
    I should hope not. This would have been covered in primary school.
    That's probably where I missed it.
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    (Original post by Srxjer)
    Yeah I tried that but 6 x 47 is 282. I wasn't to sure what to do with it.
    Where do you get 6 X 47 from?
    Basically what you've got is:
    (\frac{7}{5} * \frac{336}{336}) + (\frac{9}{6} * \frac{280}{280}) + (\frac{11}{7} * \frac{240}{240}) + (\frac{13}{8} * \frac{210}{210})
    So for the first one, it's (\frac{7}{5} * \frac{6 * 7 * 8}{6 * 7 * 8}) and that logic applies to the rest of the fractions. You cancel down and theres your answer.
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    (Original post by Srxjer)
    I know this is probably something really obvious I've missed here, but can anyone explain the workings of this? I've never come across it before and I can't find anywhere online that explains it.

    \frac{7}{5}+\frac{9}{6}+\frac{11  }{7}+\frac{13}{8}= \frac{1707}{280}

    Thanks.
    The first thing to do is to change the improper fractions into mixed numbers.
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    (Original post by steve2005)
    The first thing to do is to change the improper fractions into mixed numbers.
    The first thing after finding the LCD, you mean?
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    (Original post by steve2005)
    The first thing to do is to change the improper fractions into mixed numbers.
    No, you'd find the LCD, then add, then cancel.
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    (Original post by Wednesday Bass)
    No, you'd find the LCD, then add, then cancel.
    NO

    Add the whole numbers first. Then deal with fractions.

    eg \frac{7}{5}=1\frac{2}{5}

    If you were multiplying then , you would turn to improper fraction. BUT adding and subtracting it is easier to deal with whole numbers first.
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    (Original post by steve2005)
    NO

    Add the whole numbers first. Then deal with fractions.

    eg \frac{7}{5}=1\frac{2}{5}

    If you were multiplying then , you would turn to improper fraction. BUT adding and subtracting it is easier to deal with whole numbers first.
    Then you still have to deal with the fractions LCD, and since OP has the answer as an improper fraction, I'd say that's how it's asked for.
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    (Original post by steve2005)
    NO

    Add the whole numbers first. Then deal with fractions.

    eg \frac{7}{5}=1\frac{2}{5}

    If you were multiplying then , you would turn to improper fraction. BUT adding and subtracting it is easier to deal with whole numbers first.
    I disagree, seems to be adding an extra operation for no real gain in terms of ease.
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    (Original post by Slumpy)
    I disagree, seems to be adding an extra operation for no real gain in terms of ease.
    The arithmetic is much easier if you deal with whole numbers.

    Small children often add improper fractions BUT adults should know better.
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    (Original post by steve2005)
    The arithmetic is much easier if you deal with whole numbers.

    Small children often add improper fractions BUT adults should know better.
    Again, I would disagree.
    In fact, I don't think I've seen a proper fraction in the last year and a bit, and I've seen some quite able mathematicians.
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    \frac{a}{e}+\frac{b}{f}+\frac{c}  {g}+\frac{d}{h} = \frac{a(fgh)+b(egh)+c(efh)+d(efg  )}{efgh}
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    (Original post by steve2005)
    The arithmetic is much easier if you deal with whole numbers.

    Small children often add improper fractions BUT adults should know better.
    What's wrong with improper fractions? It's perfectly reasonable to leave an answer as one.
 
 
 
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