Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Simple Algebra Division question

  1. Jan 22, 2008 #1

    I am not grasping how to deal with multiple divisions properly.

    If I have a/1 divided by b/1 divided by c/1

    How do I know if the compressed form is ac/b or a/bc?
  2. jcsd
  3. Jan 22, 2008 #2
    It's simple: you don't.
  4. Jan 22, 2008 #3
  5. Jan 22, 2008 #4
    What poster #2 is saying, is that (a/b)/c is not equal to a/(b/c). So talking about a/b/c, without properly using parenthesis to tell which of the two cases is meant, is simply ambiguous.
  6. Jan 22, 2008 #5


    User Avatar
    Science Advisor
    Homework Helper

    i would have chosen a/(bc) as what was meant, but i see the problem.
  7. Jan 22, 2008 #6
    Is it ever possible to be working on a problem and end up with a\b\c?
  8. Jan 23, 2008 #7
    a/b/c are just written-down symbols that stand for an idea on your mind; if you work on a problem and get that result, in your mind you'll know what you mean (if you're not insane). Now, other people won't understand you unless you use parenthesis, or write something more graphical like [tex]\frac {a/b}{c}[/tex] or [tex]\frac {a}{b/c}[/tex].
  9. Jan 23, 2008 #8
    I think what this problem is lacking is parentheses! ( )
  10. Jan 23, 2008 #9


    User Avatar
    Science Advisor

    Is a/1= a, b/1= b, c/1= c? If so why write it that way?

    What does "\" mean here?
  11. Jan 23, 2008 #10

    To specify that all variables are already a fraction. Some math texts show a/b/1 is a/b and a/1/b is ab/1

    I meant / by "\"
  12. Jan 23, 2008 #11


    User Avatar
    Science Advisor

    a/b/1 can be interpreted as (a/b)/1= a/b or a/(b/1)= a/b so that's not a problem. a/1/b could be interpreted as (a/1)/b= a/b or a/(1/b)= ab. That's a problem.

    It really doesn't matter whether a or b are "already" fractions.
  13. Jan 23, 2008 #12
    Oh wow, I just figured out where I went wrong, now I see how it does not matter where the main division is located because the if all denominators are 1 then it doesnt matter if you multiply the 1 by the numberator or the denominator.
  14. Jan 24, 2008 #13
    I thought the general rule for an ambiguous case was to work from left to right and which would be ((a/1)/(b/1))/(c/1) = a/bc.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook