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Where did the 2 come from

  1. Jan 14, 2015 #1
    I need some help with this fraction problem. 8 5/6 - 1 1/3 you Need to rewrite the problem as 8 5/6 - 1 2/3 where did the two come from ?
     
  2. jcsd
  3. Jan 14, 2015 #2

    Stephen Tashi

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    Science Advisor

    Can you show the whole text of this problem and supposed solution?
     
  4. Jan 14, 2015 #3
    The problem is 8 5/6 - 1 1/3 the answer is 8 5/6 - 1 2/6 answer 7 1/2 I just want to know how they got the 2 in 2/6
     
  5. Jan 15, 2015 #4

    Mark44

    Staff: Mentor

    The expression is either 8 5/6 - 1 1/3 or 8 5/6 - 1 2/3. The two are not the same.

    Since the answer is 7 1/2, the problem must have been 8 5/6 - 1 1/3. The only explanation for 8 5/6 - 1 2/3 is that it's a typo.

    Edit: Jim, I didn't notice that you revised what you wrote in your later post. 1 1/3 is the same as 1 2/6.
     
  6. Jan 15, 2015 #5

    Stephen Tashi

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    They changed 1/3 to 2/6 by multiplying the top and bottom of the fraction 1/3 by the number 2.
     
  7. Jan 15, 2015 #6
    The question is 8 5/6 - 1 1/3 you are supposed to re write the problem as 8 5/6 - 1 2/6 what I want to know is when they changed the 1/3 to 2/6 where did the two come from
     
  8. Jan 15, 2015 #7

    NascentOxygen

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    You can multiply the top of a fraction by any number so long as you multiply the bottom of that fraction by the same AND THIS DOESN'T CHANGE THE VALUE of that fraction.

    So 1/3 is equivalent to 2/6 in all regards.

    QUESTION: Would you prefer 1 slice of a pie after the pie was cut up into 3 equal pieces, or
    would you prefer 2 slices of the same pie after it had been cut into 6 pieces?

    ANS: there is no difference!

    The decision to convert the denominator into a 6 was so that it matched the denominator of the first fraction in the problem.
     
    Last edited: Jan 15, 2015
  9. Jan 15, 2015 #8

    DrClaude

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    Staff: Mentor

    If I may propose a different way of seeing it: any number multiplied by 1 is the same number. Therefore, you can always multiply any fraction by ##n/n## (provided ##n## is not zero!):

    $$
    \frac{1}{3} = \frac{1}{3} \times 1 = \frac{1}{3} \times \frac{2}{2} = \frac{2}{6}
    $$
     
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