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Math Help - Having trouble with order of operations with fractions

  1. #1
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    Having trouble with order of operations with fractions

    Hello all. I am a newbie here and could really use some help with a math problem. I searched the boards and did not see anything similar so here goes...

    The problems is:

    Evaluate 2 20 (1/3 + 1/4) x 7

    Now I understand the basic order of operations but these added fractions are throwing me off. I made an attempt at the problem by adding the fractions which came to 7/12 which I then turned into a decimal but I know that can't be right. If someone could explain this to me, I would really appreciate it and offer many thanks in advance.
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  2. #2
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    Quote Originally Posted by dclary View Post
    Hello all. I am a newbie here and could really use some help with a math problem. I searched the boards and did not see anything similar so here goes...

    The problems is:

    Evaluate 2 20 (1/3 + 1/4) x 7

    Now I understand the basic order of operations but these added fractions are throwing me off. I made an attempt at the problem by adding the fractions which came to 7/12 which I then turned into a decimal but I know that can't be right. If someone could explain this to me, I would really appreciate it and offer many thanks in advance.
    Yes, your "order of operations" is correct. But why "turn it into a decimal"? Since the problem is expressed in terms of decimals, I would expect you to answer that way. 2- 20 (1/3 + 1/4) x 7 is, indeed, equal to 2- 20 (7/12) x 7 = 2- 20*(12/7)*7= 2- 20*12= 2- 240= -238.
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  3. #3
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    Thank you for getting back to me so quickly. Let me make sure I have this correct, I keep the fraction without changing to a decimal and just solve the problem as I normally would...is that correct? If so, boy do I feel stupid! I have been tackling that problem for most of the day.
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  4. #4
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    Yep, there's absolutely no need to convert these fractions into decimals!

    The question is given in fraction form, so you can assume the teacher/examiner/book expects the answer in fraction form also (If the answer isn't a whole number of course :P)!

    What answer did you get?
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  5. #5
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    Boy, it is hard trying to do this math stuff after 20 year of not being in school....lol! When I first did the problem, I kept wanting to change the fractions to a decimal because I couldn't figure out how to work the fractions with the rule of PEMDAS. Just when I think I am getting some where, the Professor throws a zinger out and I get lost :-)

    There were only 8 questions on this assignment and I have been 2 days trying to get them figured out...lol. There were two that was giving me a hassle, the one I posted here and one about equations. I might catch on one of these day.
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