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On April 08 2011 11:46 mahnini wrote:Show nested quote +On April 08 2011 11:38 mcc wrote:On April 08 2011 11:07 Zeke50100 wrote:On April 08 2011 11:06 jtan wrote:
There also seems to be some different use of the word ambigous.
The expression 1/x*y is unambigious in the strict computer-sience sense, but like I said, it's ambigious in the sense that a lot of people interpret it differently, you can't really argue against that. Lack of knowledge does not mean ambiguous. Problem is when none uses the rule in practice, which from my experience is the case of 1/xy. My math professors used (as seldom as they used one line notation) 1/xy as meaning 1/(xy), even though everyone knew that it is not correct according to the order of operations rule. So if you asked people there what 1/xy means the answer 1/xy = 1/(xy) would be correct as universal usage supersedes not used rule and creates new variant of the notation. I would assume a lot of math communities use it the same way ? So when OP asks his question and does not specify notation it is in fact ambiguous. You cannot always assume everyone uses the same notation. If you write (48/2)(9+3) you can assume reasonably that everyone's notation interprets it correctly. In case of OP's formulation, that assumption gets much weaker. what you say might be true but it is not a formal notation as far as i know and when you seek to communicate with people you generally follow the standards, which is, again as far as i know, the order of operations. it's a bit of a tricky question and people who got 2 made a little mistake reading the equation but that doesn't mean the equation was written incorrectly nor does it make the equation ambiguous unless you can apply another formal set of notations to that equation that would make sense.
Standard is to just not use such expressions non-locally. Asking for the value of that expression on international forum creates a dilemma, should I use a rule that kind of exists, but we don't use at all and none uses in international communication, or should I answer according to what it means locally. Of course best answer would be to just say, this expression is ambiguous/vague/not-well-formed/... please specify notation you used or to say both answers are possible and explain using which assumptions you get which answer.
And of course it is possible to create consistent formal notation that would support the second interpretation of that expression. There is just no point as expressions like that are used only locally by people who share their interpretation. Also its not like notations are mathematical truths, they change in time based on practical usage as any other grammatical rules.
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It's order of operations. That's not college level math, it's like freshman year high school math. Although I imagine people would get it wrong if they haven't had to deal with numbers in a long time or because writing out equations using a standard keyboard sucks.
+ Show Spoiler +Former engineering student.
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I know it's 288 but... Someone get Day[9] in here to explain it and help those who don't get it. He has a degree in math lol.
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On April 08 2011 13:36 CaptainMorgan86 wrote:
I know it's 288 but... Someone get Day[9] in here to explain it and help those who don't get it. He has a degree in math lol.
Uh...
Everyone knows the argument for 288 as the answer. That's why we have 100+ posts that say nothing beyond PEMDAS or BEDMAS or whatever your teacher forced on you in elementary school.
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On April 08 2011 13:32 EEhantiming wrote:
i got 2
48÷2(9+3)
48÷2(12)
48÷24=2
Except
"48÷2(12)
48÷24=2"
is an incorrect step. You do division (48÷2) to get 24 before you do the multiplication. PEMDAS. Multiplication and division are on the same tier, so you whichever one comes first from left to right.
And then 24(12) is 288.
I think it's embarrassing how over 40% of the people who took the poll got it wrong...
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1/2x should be 1/(2*x) right? everything in calculus and diffeq looks like that and thats how i've always interpreted it
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It's easy to explain. Division and multiplication are the same thing. 48 / 2 is the same as saying 48 * (1/2)
If you write the question out as 48 * (1/2) * (9+3)=? there's no ambiguity.
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Look at the amount of people that contradict themselves. If you voted 288 in the first poll, you should vote(1/2)x, if you voted 2 you should vote 1/(2x). It's kind of funny.
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288
(1/2)*x
Jesus Christ. PEMDAS. End of story.
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The disagreement is whether or not a division sign or a multiplication sign takes precedence over one another. The answer is that neither do. Parenthesis always comes first. Exponent second, and then both Multiplication and Division are grouped into the third lump, with Addition and Subtraction being lumped into the fourth group. To determine what comes first, you just read the equation left to right, and pick the first one that you see.
In this equation, 48/2(9+3)
(9+3) = 12
48/2*12
from left to right, it reads
1.) 48/2 = 24
2.) 24*12 = 288
Multiplication and division are two of the same mathematical procedure. That is to say, you get the same number when multiplying and dividing a certain number with another certain number. This means that you cannot give either multiplication or division preference over the other when taking Order of Operations into account. PEMDAS and BEDMAS are just tools taught to middle school and high school students to remember that Parenthesis trump Exponents, and that Exponents trump the others.
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Pfft, who uses the ÷ notation?
It's what lead this thread to 51 pages.
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=48 / 2(9 +3)
=48 / (18 + 6)
=48 / 24
= 2
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BEDMAS
Brackets
Exponents
Division
Multiplication
Addition
Subtraction
Simple.
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On April 08 2011 13:53 Sharkyloft wrote:
BEDMAS
Brackets
Exponents
Division
Multiplication
Addition
Subtraction
Simple.
I've always known it as PEMDAS.
It's always nice to find out different ways of remembering it 
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I think the issue is that too many people are thinking of it in this notation:
48
----
2(9+3)
Which still technically equates to 288. The issue here is that too many people are used to reading equations with variables in it. With variables there is a standard that 2(x+3) = 2x + 3. However when you do not see variables, this is not what is usually done.
If I was to write 48 / 2 * (9+3), 99% of people would answer 288, simply because they not see it in a different context. According to rules of math this is how it is to be interpreted. Using 2(9+3) notation is generally supposed to be used with variables, not integers.
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On April 08 2011 13:56 cohnvey wrote:Show nested quote +On April 08 2011 13:53 Sharkyloft wrote:
BEDMAS
Brackets
Exponents
Division
Multiplication
Addition
Subtraction
Simple. I've always known it as PEMDAS. It's always nice to find out different ways of remembering it
Yet people reach 2 not because they don't apply bedmas.
In fact, you can't reach 2 if you don't deal with the brackets first. The interpretation lies within division vs fraction
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Pretty hilarious that both arguments quote PEMDAS or BEDMAS, but the people that argue for the answer to be 2 are applying it incorrectly.
On April 08 2011 13:51 Assymptotic wrote:
Pfft, who uses the ÷ notation?
It's what lead this thread to 51 pages.
I believe the original OP used the / notation.
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And this is why you do math ona sheet of paper, not ont the computer
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this thread makes me realize how great fractions are.
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On April 08 2011 10:28 Hesmyrr wrote:Show nested quote +On April 08 2011 10:26 MajorityofOne wrote:On April 08 2011 10:21 Slithe wrote:
This thread seriously needs to be stopped. The arguments are just going in cycles. Not curious to see at what point it runs out of steam? I'm thinking 100+ pages You place too much stock on stupidity of TL. I say <50.
So close, yet so far.
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EPT
