1. Welcome! Please take a few seconds to create your free account to post threads, make some friends, remove a few ads while surfing and much more. ClutchFans has been bringing fans together to talk Houston Sports since 1996. Join us!

48÷2(9+3) = ????

Discussion in 'BBS Hangout' started by Pull_Up_3, Apr 7, 2011.

?

PEMDAS

  1. 288

    48.9%
  2. 2

    46.2%
  3. idunnololdog.jpg

    4.9%
  1. tehG l i d e

    tehG l i d e Member

    Joined:
    Feb 17, 2009
    Messages:
    27,351
    Likes Received:
    20,985
    where is Nero?
     
  2. MiddleMan

    MiddleMan Member

    Joined:
    May 20, 2005
    Messages:
    3,297
    Likes Received:
    270
    3-5+1(2+4)
    3-5+(2+4)
    3-5+6
    -2+6
    4
     
  3. tehG l i d e

    tehG l i d e Member

    Joined:
    Feb 17, 2009
    Messages:
    27,351
    Likes Received:
    20,985
    That's correct but I wanted TinyWang to do it by his convention.
     
  4. arkoe

    arkoe (ง'̀-'́)ง

    Joined:
    Dec 13, 2001
    Messages:
    10,384
    Likes Received:
    1,597
    Why is this thread 16 pages long? :confused:
     
  5. foo82

    foo82 Member

    Joined:
    Dec 4, 2006
    Messages:
    923
    Likes Received:
    31
    Technically it doesn't, but the way the equation is laid out, it is sort of implied.

    1/2A

    is technically A/2, but most people would read it as 1/(2A). When variables/numbers are clumped together without a multiplier symbol, it typically implies that you want them together.

    Another Example

    cos 3x most people see it as cos (3x) but rarely will anyone ever see it as 3cos x.

    It has nothing to do with whats outside of the parenthesis but rather it was typed out in a fashion of 2(9+3) over 2*(9+3). when typed out in the former, you are implying that you want the numbers together in the denominator. That is where the confusion is coming from is that implicit assumption people make.
     
  6. foo82

    foo82 Member

    Joined:
    Dec 4, 2006
    Messages:
    923
    Likes Received:
    31
    oops mistake in example" cos 3x most people see it as cos (3x) but rarely will anyone ever see it as 3cos x.

    I meant cos 3x most people see it as cos (3x) but rarely will anyone ever see it as xcos 3.
     
  7. Space Ghost

    Space Ghost Member

    Joined:
    Feb 14, 1999
    Messages:
    18,102
    Likes Received:
    8,551
    When I first did the equation, I came up with 2. If you solve it strictly by basic math, its very simple to see how you get 288. Its when people try to rationalize algebraically they get the order of operations mixed up.

    Forget the numbers and turn it into an algebraic equation.
    X=48
    Y=2
    A=3
    B=9

    You would read it: x/y(a+b)
    Many people are reading it incorrectly as:
    x
    ------
    y(a+b)

    the correct way to read it is:
    x (a+b)
    -- *--
    y 1‎‎‎‎‎‎‎‎

    Its not the simple math people are screwing up, its the algebra.
     
    #307 Space Ghost, Apr 7, 2011
    Last edited: Apr 7, 2011
  8. wizkid83

    wizkid83 Member

    Joined:
    May 20, 2002
    Messages:
    6,347
    Likes Received:
    850
    Cause people are calculating 2..... and are too stubborn to admit they got it wrong.
     
  9. wizkid83

    wizkid83 Member

    Joined:
    May 20, 2002
    Messages:
    6,347
    Likes Received:
    850

    As said before, write the equation exactly as stated in Excel, SAS, SQL, C++ and what ever else math programing language that can take an algorithm, and let me know which one will return the value of two.
     
  10. dback816

    dback816 Member

    Joined:
    Oct 21, 2003
    Messages:
    4,506
    Likes Received:
    160
    Because Texas
     
  11. Nero

    Nero Member

    Joined:
    Jun 12, 2002
    Messages:
    6,447
    Likes Received:
    1,429
    Hmmmm... Ok, let's actually examine this perhaps a little more than you did.


    Using your very same numbers:

    $50 in your account

    $3 debit

    $2 credit

    $5 credit

    First, you placed them in order: 50 -3 +2 +5 and came to a total of 54

    You are correct.

    Then you asked: But what if I had started from the right side and did the 2+5 operation first? Would I still get the same result?

    Well, let's find out. You didn't mention where you would like the 50, so what the heck, let's just tack it on at the end. Doesn't matter, put it wherever you want.

    Let's begin: 2 +5 (so far we have 7) -3 (oops, back down to 4) annnd +50 . Hmm. It appears that we are left with 54.

    Again.

    I suppose we could do it in another order: -3 (negative 3) +2 (negative 1) and +5 (now we are back up to 4) annd that +50 again. Shucks, 54 again.


    Ok, how about 50 + 5 -3 +2 ... Hmmm.. STILL 54.


    Ok, I am curious. Is there any combination of 2, 5, 50, and -3 that you can think of that does NOT total 54 ?


    Now before you run loose again, I know where you are losing your grip here.

    You are thinking of these numbers as mere intergers, and as the +'s and -' as 'operators'. While this may be technically correct, you are missing the fact that these are VALUES, and you cannot separate the intergers from the operators in the original problem, or you have CHANGED THE VALUES, and therefore you have CHANGED THE NUMBERS.

    When you change the order of the VALUES in a simple addition/subtraction problem, you CANNOT break apart the intergers from the operators. It is utter nonsense to think that you can.

    This is why I tried to get you to think in terms of debits and credits, because a debit is a VALUE of -X and a credit is a VALUE of +Y. They are inseparable.

    Now, having said that: yes, if you simply took the numerals in the problem, and, willy-nilly, without regard to their actual values, and rearranged both the numerals AND the +'s and -'s, then yes, the sum would be different.

    But they would not be the SAME NUMBERS. -2 is not the same as 2. 3 is not the same as -3. Etc etc.

    So, congratulations. You have successfully proven that different numbers will add up to different sums.

    This cannot possibly be unclear now.
     
  12. 3814

    3814 Member

    Joined:
    Aug 4, 2002
    Messages:
    5,433
    Likes Received:
    72
  13. macalu

    macalu Member

    Joined:
    May 19, 2002
    Messages:
    16,942
    Likes Received:
    835

    While i don't agree with your answer to the original equation that started this thread, you are correct in this assessment. rearranging the numbers in a addition/subtraction equation doesn't change the outcome. however, what jw1144 is doing is not rearranging, but changing them the value as you say.
     
  14. CometsWin

    CometsWin Breaker Breaker One Nine

    Joined:
    May 15, 2000
    Messages:
    28,028
    Likes Received:
    13,051

    Quick, Nero. Solve this equation. Prove that you are smarter than a 5th grader.

    48÷2(9+3) =
     
  15. freemaniam

    freemaniam 我是自由人

    Joined:
    Nov 18, 2005
    Messages:
    3,528
    Likes Received:
    309
    Without a doubt, I got 2 as the answer. Then I see the trap. But I will still stick with my answer.

    If the formula is written as 48÷2x(9+3), then 288 for sure.

    I blamed calculus training that created the discrepancies. You know, the f(x) thing cemented an idea to us that something attached a function (the bracket) would have to be calculated first.

    I am thinking, for those who said 288, what would you get if the formula is presented as follows:

    48÷(1+1)(9+3)
     
  16. tinywang

    tinywang Member

    Joined:
    Mar 21, 2008
    Messages:
    3,506
    Likes Received:
    351
    K I don't know what to believe anymore. Everyone is making valid arguments that I can see myself agreeing too.

    If it's not 2, then I am sorry.

    I am an idiot?? :confused:
     
  17. jw1144

    jw1144 Member

    Joined:
    Jul 29, 2002
    Messages:
    313
    Likes Received:
    3
    Trying to simplify this. All I'm trying to show is that the same associativity rules that apply to multiplication/division also apply to addition/subtraction. You must work from left to right.

    Nero keeps converting from subtraction to addition operators to prove that you don't need to worry about left to right. What I'm unsuccessfully trying to show is that IF YOU DON'T CONVERT THE ENTIRE EQUATION FROM SUBTRACTING POSITIVE INTEGERS TO INSTEAD THE ADDITION OF A NEGATIVE INTEGER and simply subtract the integers without conversion, you do indeed need to worry about the order of things. You wouldn't ever need to worry about the order of things in the multiplication/division side either if you first converted the entire equation from dividing integers to instead multiplying by their fractional inverse.

    This post tried to illustrate what would happen if the people in this thread getting an answer of 2 followed the same approach in the addition/subtraction world. But I guess he did not succeed either:
    http://bbs.clutchfans.net/showpost.php?p=6060829&postcount=249
     
  18. mfastx

    mfastx Member

    Joined:
    Dec 1, 2009
    Messages:
    10,284
    Likes Received:
    3,886
    If I remember order of operations correctly you have to take care of parenthesis before you multiply/divide so the answer would be 2.

    But what do I know right?
     
  19. Dr of Dunk

    Dr of Dunk Clutch Crew

    Joined:
    Aug 27, 1999
    Messages:
    46,615
    Likes Received:
    33,595
    FYI :

    Wolfram Alpha/Mathematica says the answer is 288.
    Google says the answer is 288.
    Matlab says the answer is 288.
    Windows calculator says the answer is 288.
    C# says the answer is 288.

    :grin:
     
  20. freemaniam

    freemaniam 我是自由人

    Joined:
    Nov 18, 2005
    Messages:
    3,528
    Likes Received:
    309
    He did not succeed because there's no parenthesis, which is the core issue that created the discrepancies here, in his illustration at all.
     

Share This Page