48÷2(9+3) =

[Arcadio]

I'm coming into this late, how the hell is the poll this close?

This is why most people voted "2":

Okay, so I will admit, as someone who voted "2" that my mistake was forgetting the "left to right" rule.

 

[novasatori]

Implied parenthesis, they are there even when you don't know it.

 

[torpid]

To be fair, if you're a coder, you're probably gonna say 2. VB, SQL, ASP, it all resolves the 2(9+3) before doing the rest.

Huh? VB and SQL do not recognize 2(9+3) as a valid operation.

VB won't even compile 48/2(9+3) and all RDBMS to which I have access (DB2, Oracle, SQL Server) return a syntax error.

If you make it 48/2*(9+3) then all resolve to 288

 

[Brainonska511]

If you make it 48/2*(9+3) then all resolve to 288

I'm surprised so many people are coming up with 2.

If you put it into the python command line as 48 / 2 * (9 + 3) you get 288, which is exactly what I would expect, since you do parenthesis first, then multiply or divide in order from left to right. The idea of 'implied parenthesis' to get 2 is somewhat absurd and you all need to go back to elementary school math.

 

[dullard]

If you put it into the python command line as 48 / 2 * (9 + 3) you get 288, which is exactly what I would expect, since you do parenthesis first, then multiply or divide in order from left to right. .

I said it before, and I'll say it again, you did this:
48 / 2 * (9 + 3)
The OP did this:
48 / 2 (9 + 3)
There is a big difference. I don't have Python, but every other math program I have spits out undefined or mentions an error. The error is the lack of the multiplication sign. 2 and 288 are both wrong because that isn't a formula that you can evaluate.

This isn't an order of operations issue. It is a lack of properly defined operations issue. There is no order when the equation isn't an equation. Those giving an answer are as wrong as those giving the "incorrect" answer.

* Excel says "Microsoft Excel found an error in the formula you entered".
* Matlab says "Unbalanced or unexpected parenthesis or bracket".
* Google converts it to an equation it can handle in some cases, but it doesn't in most cases. For example Google won't work if you do this: "2 (12) ="
* MathCad says "This variable or function is not defined above".
* Visual Basic says "Compile error: Expected: end of statement".

 

[torpid]

I said it before, and I'll say it again, you did this:
48 / 2 * (9 + 3)
The OP did this:
48 / 2 (9 + 3)
There is a difference. I don't have Python, but every other math program I have spits out the correct answer "undefined" or "error". The error is the lack of the multiplication sign. 2 and 288 are both wrong because that isn't a formula that you can evaluate.

I can't imagine the above is going to be valid in very many programming languages. Perhaps matlab or lisp? It's been a while since I've used either but both have unique ways of interpreting parentheses from what I can recall.

 

[Paul98]

I said it before, and I'll say it again, you did this:
48 / 2 * (9 + 3)
The OP did this:
48 / 2 (9 + 3)
There is a big difference. I don't have Python, but every other math program I have spits out the correct answer "undefined" or "error". The error is the lack of the multiplication sign. 2 and 288 are both wrong because that isn't a formula that you can evaluate.

This isn't an order of operations issue. It is a lack of properly defined operations issue. There is no order when the equation isn't an equation.

so what answer would you get if you did 48/2*(9+3)?

 

[Saint Nick]

Well, if I were sticking to what I learned a long time ago, I would READ and EVALUATE the expression like this:

48 / 2 * (9 + 3)
48 / 2 * 12
24 * 12
288

Now, if it were written like this, 48/[2(9+3)], then I would read and evalute it like this:

48 / [2(9+3)]
48 / [2(12)]
48 / [24]
2

or

48 / [2(9+3)]
48 / (2*9 + 2*3)
48 / (18 + 6)
48 / 24
2

 

[dullard]

so what answer would you get if you did 48/2*(9+3)?

That is easy, 288. But, as you known, that isn't what was asked.

 

[Paul98]

That is easy, 288. But, as you known, that isn't what was asked.

Sure it was, that is how it is commonly written.

 

[dullard]

Sure it was, that is how it is commonly written.

No, it is not. Commonly, there is a multiplication sign or a small dot. Maybe you are mistaking the small dot as being invisible.

 

[rcpratt]

No, it is not. Commonly, there is a multiplication sign or a small dot. Maybe you are mistaking the small dot as being invisible.

Come on now. I agree it's poor form, but equations are written that way very commonly.

 

[Paul98]

No, it is not. Commonly, there is a multiplication sign or a small dot. Maybe you are mistaking the small dot as being invisible.

Actually it is, I just opened a couple of my old college math books, along with looked at some of my homework that I had written and tests that I had. Flipping though them I did not see a single time where there was a dot, *,... What I did see was a lot of 5ab, 12(...),...

So yes it is commonly used.

Now maybe in very low level math they still use * with expressions like that I am not sure I don't have those books.

 

[Avalon]

people that are choosing 2 are fucking trolling

lololololololol

 

[JoeBleed]

Multiply and divide are even, as are addition and subtraction. A number being outside of but next to a parentheses is that same as if there was a multiply sign. I don't have a math degree, I have a computer science degree, but this is basically just an algorithm.

Yes, I and the first one i asked, seemed to forget the left to right part for some reason.

 

[airdata]

without implying brackets though... isn't the 2x a part of the parenthesis even though it's outside of them?

But yeah.. who the hell cares and why is there a near 20 page thread about some obscure algebra problem?

/thread

 

[Paul98]

without implying brackets though... isn't the 2x a part of the parenthesis even though it's outside of them?

But yeah.. who the hell cares and why is there a near 20 page thread about some obscure algebra problem?

/thread

Why just the 2? and not the 48/2 as part of the parenthesis?

I mean what if you had (48/2*9 + 48/2*3) then decide to pull out the 48/2 and get 48/2(9+3)

 

[ussfletcher]

No, it is not. Commonly, there is a multiplication sign or a small dot. Maybe you are mistaking the small dot as being invisible.

When you have a number directly next to a parenthesis that is an abbreviation, it has an implied multiplication sign.

 

[ussfletcher]

Why just the 2? and not the 48/2 as part of the parenthesis?

I mean what if you had (48/2*9 + 48/2*3) then decide to pull out the 48/2 and get 48/2(9+3)

I believe that is what they are doing.

But your example is correct, if you evaluate it you get 288...

 

[sactoking]

So you're saying that because a "/" was used, we have to assume that anything following it is the denominator? Is that a rule explicitly written anywhere? Also, the OP actually uses the symbol "÷" to imply division, and not "/." Does that change things?

I'm not saying we have to, I'm just saying we do.

Once you get into algebra in junior high or high school division becomes a lot less straightforward. You're no longer looking at 20÷5 or 4|64, you're looking at [3(a+b)]/[(x+3)(x-3)]. At this point in most students' minds the symbol "/" really stops meaning 'divided by' and starts meaning 'divisor'. The symbolic meaning is less of a verb and more of a noun from that point forward.

In student shorthand 3(a+8)/7(z-5) is an acceptable representation of what some here would want shown as [3(a+8)]/[7(z-5)] or what might be written as
3(a+8)
7(z-5)

It is not an attempt to show
3(a+8)(z-5)
7
which might be a literal interpretation of what was written.

The use of "/" becomes a simple representation for 'everything to the left of the divisor is the numerator and everything to the right of the divisor is the denominator'.

Beyond that the use of "÷" is easily mentally juxtaposed to "/" through the penetration of computers. "÷" is an 'outdated' symbol in the digital world. It doesn't appear on a standard keyboard and I had to look it up in an ASCII table to know it was alt246. I wouldn't be surprised if people saw "÷" and immediately thought "/" which as explained can easily be interpreted as a noun and not a verb in the context given.

 

[Matthiasa]

Right, by other sources - good call.

Such as TI on older calculators and on their newest one as well.
Oh and some academic stuff but that doesn't matter right?

 

[roguerower]

When you have a number directly next to a parenthesis that is an abbreviation, it has an implied multiplication sign.

Yes. 12 years of grade school and 4 years of higher education math agree with this statement.

 

[soulcougher73]

without implying brackets though... isn't the 2x a part of the parenthesis even though it's outside of them?

But yeah.. who the hell cares and why is there a near 20 page thread about some obscure algebra problem?

/thread

I think people care because somewhere in our education system some are failing to teach algebra correctly. The big problem seems to come if you interperet the "/" symbol as a division symbol or a fraction symbol.

Since its a one line equation i personally inteperet it as a division symbol. If it was a fraction symbol i would have used another line to make it a 2 line equation. That is just me and the way i was taught...pre computers

 

[Cogman]

288

Division and multiplication are on the same "level", in that case, you preform operations from left to right. Wolfram Alpha agrees with me.

This is why we need RPN

24 2 / 9 3 + * is so much clearer

 

[Paul98]

I'm not saying we have to, I'm just saying we do.

Once you get into algebra in junior high or high school division becomes a lot less straightforward. You're no longer looking at 20÷5 or 4|64, you're looking at [3(a+b)]/[(x+3)(x-3)]. At this point in most students' minds the symbol "/" really stops meaning 'divided by' and starts meaning 'divisor'. The symbolic meaning is less of a verb and more of a noun from that point forward.

In student shorthand 3(a+8)/7(z-5) is an acceptable representation of what some here would want shown as [3(a+8)]/[7(z-5)] or what might be written as
3(a+8)
7(z-5)

It is not an attempt to show
3(a+8)(z-5)
7
which might be a literal interpretation of what was written.

The use of "/" becomes a simple representation for 'everything to the left of the divisor is the numerator and everything to the right of the divisor is the denominator'.

Beyond that the use of "÷" is easily mentally juxtaposed to "/" through the penetration of computers. "÷" is an 'outdated' symbol in the digital world. It doesn't appear on a standard keyboard and I had to look it up in an ASCII table to know it was alt246. I wouldn't be surprised if people saw "÷" and immediately thought "/" which as explained can easily be interpreted as a noun and not a verb in the context given.

That is very sloppy, and complicates things especially when you want to have more stuff after the / that isn't the denominator. If I write 1/2 + 3 it should mean exactly what it says, I should not have to figure out if something is implied or not.