Sidebar Sidebar
Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.

Solve this simple math problem: 48/2(9+3)

288 or 2 ?

  • 288

    Votes: 154 48.4%

  • 2

    Votes: 164 51.6%
  • Total voters
    318
Status
Not open for further replies.
For the record, I am sad that 2 is winning (or even close) to 288. But it does help explain one thing - a reason why so many people I try to tutor/help with math cannot seem to understand basic algebra operations is because nearly 50% of people do not understand order of operations (this was roughly the same percentage on the physics poll linked to earlier) :(

No wonder people have so much trouble with doing algebra correctly :eek:
 
You cannot distribute the 2 to the parenthesis because its binded by a division sign. You can only distribute if 48 was being added or subtracted from the 2.


vincenz said:
I got 24 * 24. Which is 288. I can't believe how long this thread is. And someone needs to fix the way the Mac does math...
Click to expand...
I can't tell if you are being sarcastic.
Not so fast, 24*24 is not 288.
 
I wish there was a poll option of who is getting 288 and is say in a technical field such as engineering/stats/physics, etc

My guess is that 288 is coming from people who use math extensively and 2 coming from those who may not...
 
McGiord said:
Wrong.
Click to expand...

Ok then you do not know how to follow the order of operations....ie if you want 2, you have to have another set of parenthesis (so you evaluate 2(9+3) before dividing into 48) or mistakenly think that multiplication somehow supersedes the use of division (which it does not and you then proceed from left to right)
 
dukebound85 said:
Ok then you do not know how to follow the order of operations....ie if you want 2, you have to have another set of parenthesis (so you evaluate it before dividing) or mistakenly think that multiplication somehow supersedes the use of division
Click to expand...

Please go back and read my previous posts.
 
In my opinion-

48/2(9+3) = 288

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

To make it clear you could write it with ( ... )^-1 like a real man! :D
 
iStudentUK said:
In my opinion-

48/2(9+3) = 288

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

To make it clear you could write it with ( ... )^-1 like a real man! :D
Click to expand...

By adding the second set of (), you changed the equation, therefore the two different answers. As written in the original way, the answer 2 is clearly wrong.
 
Rodimus Prime said:
I would not call it bad style but pretty clear that people all over the world suck at math.
I can not even remember the last time I used the paper notation over '/' in my work. That paper notation is harder to write and read for me as it can easy be confused with '-' if the dots are missed or poorly put in place.
The correct way to read 48/2(9+2) is (48/2)*(9+3) no other way about it. I would write it 48/2(9+3) because that is clear what it should be and under the rules that is exactly what I was aiming for. If I wanted it to be 48/ ((2*(9+3)) I would write it that way or have the 48 above a longer line and the 2 (9+3) completely below it.
Click to expand...

highlighted for comedy effect ;)

well it depends how your learned your paper notation ... in austria the division notation is simply the two points ' : '

personally i would have rather written it down like this for computer use:
48 / 2 * (9+3)
or used
 
McGiord said:
Please go back and read my previous posts.
Click to expand...

and?

You essentially say that math, which humans use as a language, is taught incorrectly in regards to evaluating expressions because there is a "right way" of doing it without going into how one should evaluate it.

Order of operations is paramount to understand as it is a fundamental concept yet you state that following the order of operations is wrong in this case...why?
 
Mac'nCheese said:
By adding the second set of (), you changed the equation, therefore the two different answers. As written in the original way, the answer 2 is clearly wrong.
Click to expand...

I'm not saying that 2 is an incorrect answer, the equation is ambiguous. However, I assume the equation is written that way because it is done on a forum without formula writing ability and writing-

48(9+3) = 288
2

is clumsy. So the "_" is replaced by a "/". If the author wanted the equation to be-

__48__ = 2
2(9+3)

He would have made it clear when converting into "/", by adding a second set of brackets.

In other words, when using "/" I assume only the function immediately following forms the denominator unless there are brackets to indicate otherwise. This is based on the assumption that no reasonable mathematician would use the childish "/" instead of "_" unless constrained by their tools. As I said earlier, making it ( ... )^-1 would remove any ambiguity.
 
iStudentUK said:
I'm not saying that 2 is an incorrect answer, the equation is ambiguous. However, I assume the equation is written that way because it is done on a forum without formula writing ability and writing-

48(9+3) = 288
2

is clumsy. So the "_" is replaced by a "/". If the author wanted the equation to be-

__48__ = 2
2(9+3)

He would have made it clear when converting into "/", by adding a second set of brackets.

In other words, when using "/" I assume only the function immediately following forms the denominator unless there are brackets to indicate otherwise. This is based on the assumption that no reasonable mathematician would use the childish "/" instead of "_" unless constrained by their tools. As I said earlier, making it ( ... )^-1 would remove any ambiguity.
Click to expand...

Agreed again.
 
wow

I must say i just found this sight through google and had to join because of this post. I am a math teacher and the correct answer is 2

48/2(9+3) is a different equation than 48/2 * (9+3)

using Pemdas or the correct order of operations in the first problem
we first add whats in the parentheses (9+3)= 12
second step we multiply 2(12) =24
final step 48/24 = 2

the people who are getting 288

are adding (9+3) =12
then they are skipping an order of operations and going straight to division 48/2 =24
24 * 12 = 288
 
I agree with I student UK using the constraints of / makes it rather ambiguos (did I spell that right) as I originally read it. I believed the 2(9+3) to be in the denominator in which case the answer is clearly 2
 
Finallyfamous said:
I must say i just found this sight through google and had to join because of this post. I am a math teacher and the correct answer is 2
Click to expand...

Welcome to the site! :)

I disagree for the reasons I stated just above.

Using "/" is only appropriate for "x/y" type functions. Anything more complex should use "_". Therefore, "/" is only used here because it is on a forum and so "_" looks clumsy. I'm looking at what I think the author would have written on paper, and I think that would have been the option that leads to 288.

EDIT- just saw your 2nd post. This is confusing. I originally saw it as 48/2 (9+3), and to me the space would also have made clear the answer is 288. However, then I saw there was no space!
 
Finallyfamous said:
I agree with I student UK using the constraints of / makes it rather ambiguos (did I spell that right) as I originally read it. I believed the 2(9+3) to be in the denominator in which case the answer is clearly 2
Click to expand...

You can't assume that 2(9+3) is under the denominator

They way it is explicitly written is interpreted to be (48/2)*(9+3)
 
Status
Not open for further replies.
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.
Top Bottom
Back