Poll: What is the answer to 48/2(9+3)?

[flippedthebitch]

I'm pressed for time so I'll do this as fast as possible and I think a lot of people already said this but here's my 2 cents as they say.

48/2(9+3) the way I was thought works out like so

You start out with the parenthesis getting 9+3 = 12

Then you procceed with the multiplication and division going from left to right

coming to the conclusion that the full equation would be something like 48/2(9+3) = 48/2(12) = 24(12) = 24x12 = 288

THAT. IS. HOW. YOU. DO. IT!

If anyone thinks different, they don't know math or their teachers didn't get through to 'em.

Incidentally I think that while you might say the the multiplicatin symbol should be added before the parenthesis I believe that when I was doing this level of math they started out doing that to put emphasiz on the fact that it's supposed to be there, but in the end if there's a parenthesis in an equation you're supposed to know that the numbers preceeding it are supposed to be multiplied by it. After the parenthesis is calculated mind you. And either way it doesn't matter if a multiplication sign is there or not because if we follow the calculate from left-to-right rule and the equation looked like this

48/2x(9+3) we'd still end up with
48/2x(12) paranthesis done
24x(12) Division done - 48/2<<this one first cause, left to right remember?
288 - Final multiplication of the two sets of numbers.




Now. Is that bloody clear enough for you?!

Edit: wow.. keyboard kind of got away from me there. Anyway. I stand by this.

Seriously, there is no "left to right" in math

What if you look at s simple question like 5-3+2? Do you not read this left to right? So according to "BEDMAS" or whatever we have to do all addition before subraction? Its the same princible with muliplication and division. One doesnt take priority over the other. The equation is solved left to right unless an operation is included inside parenthesis or brackets to indicate that they should be completed before other operations in the question. The acronym BEDMAS or PEMDAS or whatever helps us to remember the priority of brackets over exponents over multiplication and division over addition and subtraction. Hell, in new canadian curriculum "subraction" isn't even considered a proper term anymore, its "adding a negative" to deter students from making mistakes just like the ones you are making.

I should know, I am right in the middle of my 5 week practicum teaching algebra to grade 8 and 9 students to finish up my 3rd year of a mathematical education degree at the university of alberta. I know what I am talking about. Multiplication and Division never inherently get division over one another, so reading the equations left to right is nessessary.

 

[idodo35]

well thats oviosly 2 i mean
48/2(9+3)
48/2*12
48/24
2

 

[Quazimofo]

I don't know why you want us to do your homework for you, but I got 288... after you do the parentheses, you're supposed to do them from left to right. I think it's a poorly written problem, though.

lol it's not a homework problem man, I'm not in middle school. This question is blowing up other forums and reddit.

48/2(12) = 2

Yeah, that's how I did it. But the way it's written, it doesn't specify if the only the 2 is being multiplied by 12 or if the entire fraction is. If the first, then it's 2. If the second, then it's 288.

So, as Professor Layton wisely pointed out, the problem is poorly written.

not really. due to the limitations of computers, we cant write fractions on forums quite as well as by hand, so one must assume that since the whole fraction was not in parenthesis to be multiplied, the multiplication by 12 only applies to the denominator of the fraction. and so, by adding (9+3) to get 12, then 12*2 to get 24, 48/24=2. simple

yay high school freshman pre calc class!

Hmmmmm. You should pay a little more attention in your calc class. If the intentionn was for the 9+3 to be applied only to the denominator then that would have to be expressed with parenthesis. When this isn't specified, then we do the operations of division and multiplication in order from left to right. So:

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

When a multiplication and division step takes place in the same equation and the second operation isn't included in parenthesis to indicate that the question requires you to complete that operation first we have to read the question left to right. This is the way calculators would solve this problem. Of course if the question was written (48/2)*(9+3) it would remove all ambiquity.

Yay for 3rd year university mathematics

hmm, i see your point. i guess the first poster really is right in that the way the problem is written allows it to be easily taken either way, and so unless the writer had a specific way in mind, this is a debate that will never have a clear winner or right answer.
and which university? im just curious.

 

[Slanzinger]

C++ throws a hissy fit, thinking that I'm trying to call a function named 2 with the argument 12.
Without being more specific there it has to be interpreted left to right rather than implicating the 12 into the denominator - if you were to add a * between the 2 and the bracket then I would see it as the two being separate - that is, the 12 is multiplying the fraction rather than being part of the denominator.
Better ways of phrasing it to make it a hell of a lot less confusing would be 48(9+3)/2 or 48/(2(9+3)). Though I guess the ambiguity was what you were going for anyway.

 

[Halceon]

I don't know why you want us to do your homework for you, but I got 288... after you do the parentheses, you're supposed to do them from left to right. I think it's a poorly written problem, though.

lol it's not a homework problem man, I'm not in middle school. This question is blowing up other forums and reddit.

48/2(12) = 2 using PEMDAS

So a bunch of forums and reddit are blowing up, because somebody doesn't failed at proper notation?

I could equally ask the question, whether 19+2$4/9 equals 91 or 77.

Mmmyeah, I've never had much faith in the average man being intelligent, but this is just disappointing.

 

[flippedthebitch]

lol @ zealots who only know one way of performing a mathematic solution.

Preforming a mathematic solution? Is this a musical number?

 

[kabooz18]

Since a fraction works like two brackets divided so the only right ways to write it without a fraction are "*without solving or leaving out any brackets*" (48)÷(2*(9+3)) or (48)2*(9+3)) or (48)/(2*(9+3)) that is why it can only be 2

when it's not written as a fraction and there are no addition or subtraction operators then it's like (a)÷(b) and since they are here in brackets
( "*(9+3)" is the same as writing "*12" ) and the bracket is preceded by a multiplication operator

that is why the division operator is so special^^
just sad that almost noone seems to have learned that at school.

seems google hasn't set the right parameters for divisions

 

[Bearjing]

I was taught that the / represented a fraction, and that there was ultimately no difference between fractions and division. Under those rules, if we were expected to see

48
----(9+3)
2

as opposed to

48
-----
2(9+3)

the problem would be written as

(48/2)(9+3)

However, the problem is written as 48/2(9+3), which makes it a fraction with 48 in the numerator, and 2(9+3) in the denominator. Any math people want to take a look at this interpretation?

Ok lets use PEMDAS (and yes you use left to right first when dealing with operators on the same level).

You first solve(simplify) what is in the parenthesis. So...
48/2(9+3)=48/2(12)

Now realize when something is in a parenthesis next to another number or variable or w/e, it means the same thing as x or *. so...
48/2*12

Since division and multiplication are on the same level you solve the first one on the left side then keep going right till it is finished. so..
48/2*12=24*12 then 24*12=288

 

[mps4li3n]

Seriously, there is no "left to right" in math. Here is the most sensible post in the whole thread:

But whatever system you use, there is no left to right.

Yeah, i don't remember that rule from school (or tutoring) either...

I'm guessing it must be because of computers and how they're programmed.


But multiplication and division do have the same precedence, so the formula is written in a confusing manner. Especially if like me you never actually encountered "/" being used as division in school (we used ":", which is so much better, but it's already used in programming for other things)...



I think this is more of a problem like using "," or "." for decimals... lack of actual long term consensus or at least wide spread knowledge of any official stance on how it's written is the problem.

 

[Jcw87]

There's a lot of people saying 'both are correct because the problem is ambiguous', but when you are faced with an ambiguous problem, you are supposed to refer to the order of operations, which guarantees only one correct answer for a simple evaluation problem like this. Now, I never needed any stupid, misleading acronyms to remember this. I just memorized it properly, and Wikipedia agrees with my memory.

terms inside brackets
exponents and roots
multiplication and division
addition and subtraction

Start with the obvious:

48/2(9+3)
48/2(12)

The key thing to notice from the order of operations is that multiplication and division have the same priority. Now, since our knowledge of math comes from cultures where written language is left-to-right, this is also how we solve the problem.

48/2(12)
24(12)
288

Why is this still being debated?

 

[ZeroAE]

Ah , I know what you did there!
You need to multiple 2 with the numbers of the parentesis , and then divide with 48.
Many people forget that.

 

[Wolfenbarg]

You need another grouping symbol to indicate whether everything after the / is the denominator. If that's the case, then it's two. If that isn't the case, it's written very poorly, and the answer is 288.

 

[Lunar Shadow]

Seems to be a bit of a culture break.
I think both parties are tight, it just depends on the way there instructors wrote stuff out. In my experience the 2(9+3) is in the denominator, as it is written without a multiplication sign which implies it is (2(9+3)). This is just badly written, as it should be clarified as the following: (48/2)(9+3), 48/(2(9+30)), or 48/2*(9+3)

Edit: Or better yet: 48 48
_____ or ___ * (9+3)
2(9+3) 2

 

[Albino Boo]

Speaking as a former accountant the correct answer is "what would you like it to be?"

 

[Natasha_LB]

I got 288, but what has really amused me is how many variations of BODMAS there are:

1. BODMAS
2. BIDMAS
3. BEDMAS
3. PODMAS
4. PIDMAS
5. PEDMAS

I find it funny how we all have slightly different terms for it. Dose anyone know any more variations?

 

[Taluien]

That's 2. If I knew all the fancy vocabulary for math in english I could tell you why, but for convenience I will just try to write it in a way that shows what I mean:

(48)/[2*(9+3)]

Sure, writing it like this makes it more complicated but shows what I mean, using the simple rule of "What to solve first": () before /* before +-

 

[Quazimofo]

I was taught that the / represented a fraction, and that there was ultimately no difference between fractions and division. Under those rules, if we were expected to see

48
----(9+3)
2

as opposed to

48
-----
2(9+3)

the problem would be written as

(48/2)(9+3)

However, the problem is written as 48/2(9+3), which makes it a fraction with 48 in the numerator, and 2(9+3) in the denominator. Any math people want to take a look at this interpretation?

yeah this is the way i was taught. but there is equally good logic for both ways to approach the problem (left to right, as opposed to making it a fraction). so, unless we ask the creator of the problem whether it was intended as a fraction or regular problem, there is no real way to find the intended solution.

and i am hardly a math person, (freshman in high school pre-calc and getting a solid B is not much in the way of credentials), but i see no flaw in the way you interpreted it. because there does not seem to be a function on most (if any) keyboards which allows for writing of fractions as we do on paper. so your approach makes as much sense as the other approach which gets 288.

 

[Bearjing]

Seems to be a bit of a culture break.
I think both parties are tight, it just depends on the way there instructors wrote stuff out. In my experience the 2(9+3) is in the denominator, as it is written without a multiplication sign which implies it is (2(9+3)). This is just badly written, as it should be clarified as the following: (48/2)(9+3), 48/(2(9+30)), or 48/2*(9+3)

2(9+3)=2*(9+3)

 

[Quazimofo]

I got 288, but what has really amused me is how many variations of BODMAS there are:

1. BODMAS
2. BIDMAS
3. BEDMAS
3. PODMAS
4. PIDMAS
5. PEDMAS

I find it funny how we all have slightly different terms for it. Dose anyone know any more variations?

no i think that covers them all, and you wrote 3 twice, it should go to 6, not 3,3,4,5

 

[OldRat]

There's a lot of people saying 'both are correct because the problem is ambiguous', but when you are faced with an ambiguous problem, you are supposed to refer to the order of operations, which guarantees only one correct answer for a simple evaluation problem like this. Now, I never needed any stupid, misleading acronyms to remember this. I just memorized it properly, and Wikipedia agrees with my memory.

terms inside brackets
exponents and roots
multiplication and division
addition and subtraction

Start with the obvious:

48/2(9+3)
48/2(12)

The key thing to notice from the order of operations is that multiplication and division have the same priority. Now, since our knowledge of math comes from cultures where written language is left-to-right, this is also how we solve the problem.

48/2(12)
24(12)
288

Why is this still being debated?

Because, for some god-awful reason, every time you ever post a math problem on a public forum, no matter how very damn basic, there's bound to be some people who either don't know but think they do, or can't be arsed to think.
Still, people screwing up something this basic just hurts my face and, despite everything, makes me somewhat depressed. I solved this in around two seconds without even thinking about it, and my math grades were piss-poor and my math classes few and far between.

But yes, this is really goddamn simple. Parenthesis go first. After that, multiplication and division are equal, so you go from left to right. AND THAT'S THAT, amazingly enough.