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

[Aurgelmir]

If I copy paste that into Excel I get 288.

all in all the problem is poorly written.

 

[mps4li3n]

2... still remember from grade school, Please Excuse My Dear Aunt Sally; Parentheses, Exponent, Multiply, Divide, Addition, Subtract. So... 9+3=12, 12*2=24, 48/24=2.

you remember wrong. you don't solve multiply before divide, they're equal, as are addition and subtraction. that's because dividing is multiplying by a number between 0 and 1 (dividing by 2 is multiplying by 1/2 = 0.5). subtraction same thing, it's addition with a negative number (6 + (-1) = 5)

... *looks*

Yep, you're right. They are the same rank, so you go left to right. That means the answer is 288 if it's written like that. Nice catch.

it's a nice way to remember though :O

Which is probably why we weren't taught any left to right rule here, it's unneeded as you can simply use actual rules of math instead of an artificial one like l->r.


Like i've been saying, it's an interpretation problem, very likely caused by new uses of symbols that haven't had the time to be made into hard rules everywhere.

Basically on paper the difference between "1/2+3" and "1/(2+3) written without ()'s" is easily apparent, while on a computer it's not... same with 2 at the power of x... (that's what 2^x is right?) Except that unlike with the powers the symbol used on the computer isn't distinctive enough... and judging by how even some programs don't get it the same there's not yet a standard that's been embraced by all.

 

[Socken]

I pity people who seriously get 2 as the answer.
Your education system teaches you stuff wrong. Period.

 

[a1el]

288
http://www.wolframalpha.com/input/?i=48%2F2%289%2B3%29

 

[mps4li3n]

And i'm sure you where also taught that 1,250 isn't 1 and 1/4 either and always assume it's one thousand etc...

Huh?

1 1/4 = 5/4 = 5:4 = 1.25
or
1 1/4 = 1 + 1/4 = 1 + 0.25 = 1.25

0 at end is not needed.

It's needed to make a point.... and there's no math rule that says i'm not allowed to use it anyway. And yes, we use "," for decimals here... and it's not Britain (they use ".", the US is on the imperial system, guess where "imperial" comes from -though i'm not sure the "." is officially part of it or it's just weight and lenght, never thought of checking-)

 

[milna64]

If I was to write 48/(2(9+3)) I would probably just write 48/2(9+3). I would write (48/2)(9+3) as either (1/2)48(9+3) or 48(9+3)/2. To split up the equation the way it has been split up suggests that it wants you to do it 48/(2(9+3)), although technically not correct.

 

[mps4li3n]

I pity people who seriously get 2 as the answer.
Your education system teaches you stuff wrong. Period.

You can't teach the wrong symbols for math... not any more then you can teach someone the sound he should make when pronouncing A in french is wrong because it doesn't sound exactly like the english version.


Like i said a million time IT'S NOT A MATH ISSUE!!!! People are interpreting it based on the assumption they where taught to make about what a symbol means in relation to math...

And because it doesn't use the symbols that are more widely recognized, like (), as much as it could it lead to problems.

 

[pejhmon]

you need another set of brackets since this is the kind of thing you can't tell unless it's written out properly.

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

[48/2] x (9+3) = 288

But the way you have written it implies that the answer is 2 is the beginning of the bracket is right next to the 2 on the base of the fraction. If there was a space between the bracket and the 2 then it may imply the answer to be 288.

 

[mps4li3n]

If I was to write 48/(2(9+3)) I would probably just write 48/2(9+3). I would write (48/2)(9+3) as either (1/2)48(9+3) or 48(9+3)/2. To split up the equation the way it has been split up suggests that it wants you to do it 48/(2(9+3)), although technically not correct.

Because technically one wouldn't run into this problem before computers stopped using punch cards.

And why do you guys use two sets of ()... not [] or {} where you're from? Or just ease of use? Because ease of use (on computers) is what this is all about really.

 

[TiefBlau]

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

PEMDAS is a misleading term. Multiplication and division are on the same hierarchy, just like subtraction and addition. You wouldn't say 4-3+2 is 4-(3+2), would you? Of course not.

So 48/2(9+3) = 48/2(12)
= 24(12) Since elements of equal hierarchy go left to right
= 288

Honestly, this isn't difficult. Whoever taught you PEMDAS clearly didn't teach you enough about it. The fact that this is a "controversy" is very disconcerting.

I pity people who seriously get 2 as the answer.
Your education system teaches you stuff wrong. Period.

You can't teach the wrong symbols for math... not any more then you can teach someone the sound he should make when pronouncing A in french is wrong because it doesn't sound exactly like the english version.


Like i said a million time IT'S NOT A MATH ISSUE!!!! People are interpreting it based on the assumption they where taught to make about what a symbol means in relation to math...

And because it doesn't use the symbols that are more widely recognized, like (), as much as it could it lead to problems.

No, it most certainly is a math issue. People have been taught the order of operations wrong if they got 2. There's no room for interpretation here any more than there is room for interpretation as to what 4-3+2 equals (spoiler: it's not -1).

 

[mps4li3n]

If I was to write 48/(2(9+3)) I would probably just write 48/2(9+3). I would write (48/2)(9+3) as either (1/2)48(9+3) or 48(9+3)/2. To split up the equation the way it has been split up suggests that it wants you to do it 48/(2(9+3)), although technically not correct.

And that would be quite inconsiderate of you... whenever i had to write something like that on a forum i've always used () and stiff to make it clear what i meant because i can see why it could be confusing.

 

[Woodsey]

BODMAS.

B(rackets)O(rder)D(ivision)M(ultiplication)A(ddition)S(ubtraction).

So 288.

I pity people who seriously get 2 as the answer.
Your education system teaches you stuff wrong. Period.

You can't teach the wrong symbols for math... not any more then you can teach someone the sound he should make when pronouncing A in french is wrong because it doesn't sound exactly like the english version.


Like i said a million time IT'S NOT A MATH ISSUE!!!! People are interpreting it based on the assumption they where taught to make about what a symbol means in relation to math...

And because it doesn't use the symbols that are more widely recognized, like (), as much as it could it lead to problems.

Of course its a maths issue. There's an established order you go through, you can't interpret any which way you like.

 

[Togs]

BIDMAS says its 288

(BIDMAS= Brackets Indices Division Multiplication etc)

 

[William MacKay]

288 using BODMAS (brackets, order, division, multiplication, addition, subtraction).
48/2*(9+3)
=48/2*(12)
=24*12
=288.
never heard of PEMDAS (scottish education system FTL)

 

[Da_Vane]

The answer is 2. When following PEMDAS/BODMAS you need to solve brackets first. This doesn't mean reduce the contents within the brackets to a single number, but removing the brackets completely.

Thus, not only do you need to solve 9+3 to get 12 first, you also need to solve 2(12) because this is still part of solving brackets. This gives you 24.

The fact that this method also backs up the implied format that this is a fraction, where both parts automatically imply brackets, means it is the correct solution. The question is best viewed as (48)/(2(9+3)).

To reach the answer as 288, the question would have to be written as (48/2)(9+3), which is such a deviation from the norm, that it would have to specifically written as such.

Oh, and for the record, 48/2x 24x. The correct answer is 24/x. 48x/2 = 24x. Thus, using substitution, we still arrive at the answer 2 for this equation, given that x=9+3 or 12.

 

[Daverson]

2(9+3) = 24
48/24 = 2

That's pretty standard. You'd be better off writing it like this:
48
--
2(9+3)
To avoid confusion with this:
48
--(9+3)
2
Which would be written like this (42/2)(9+3)

(Gah, stupid unicode not showing up right... should be able to use U+2015 instead of minus signs to denote division...)

 

[b3nn3tt]

The answer is 2. When following PEMDAS/BODMAS you need to solve brackets first. This doesn't mean reduce the contents within the brackets to a single number, but removing the brackets completely.

Thus, not only do you need to solve 9+3 to get 12 first, you also need to solve 2(12) because this is still part of solving brackets. This gives you 24.

The fact that this method also backs up the implied format that this is a fraction, where both parts automatically imply brackets, means it is the correct solution. The question is best viewed as (48)/(2(9+3)).

To reach the answer as 288, the question would have to be written as (48/2)(9+3), which is such a deviation from the norm, that it would have to specifically written as such.

Oh, and for the record, 48/2x 24x. The correct answer is 24/x. 48x/2 = 24x. Thus, using substitution, we still arrive at the answer 2 for this equation, given that x=9+3 or 12.

This. Also, does anyone else think that maybe the question is a troll, given how ambiguously it's written?

I read it that the 2(9+3) was its own entity; ie. you have to multiply it out, rather than treating the 2 as the bottom of a bracket and the (9+3) as a separate multiplier. So, doing it this way, you get 2(9+3)=(2x9)+(2x3)=24. You then divide 48 by this, giving you 2

I think the main dispute here comes from the reading of the question. Personally, I'm interested in knowing if this is a cultural thing. I'm English, and I'm curious as to whether the other people who got 2 as their answer are also English, or at least European

 

[Insomniac55]

It's 288. You would only consider 2(9+3) to be entirely in the denominator if it was written that way, which it isn't in text form. If you wrote it by hand it would be much less ambiguous.

As written, it reads like this, leading to an answer of 288:

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


As opposed to:

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

Which obviously equals 2.

There is NOTHING in the question, as written, to suggest that the second form is true. Therefore the convention is to read it the first way.




Also,

The answer is 2. When following PEMDAS/BODMAS you need to solve brackets first. This doesn't mean reduce the contents within the brackets to a single number, but removing the brackets completely.

This is completely wrong. You simplify what's inside of the brackets first, then you treat the simplified result as a regular term which has the operation outside of it applied according to the correct order of operations in regards to the whole question.

And regardless, in this question there is no 2(9+3). 48/2(9+3) is the SAME as (48/2)(9+3). It is NOT the same as 48/(2(9+3)). The reason we don't use the second set of brackets when we handwrite 48/(2(9+3)), is because the length of the fraction bar (correctly called a vinculum) implies which numbers are grouped together. When using a forward slash, this is no longer the case so we assume that it is to be read as (48/2)(9+3), which can also be written as 48(9+3))/2.

I'm not an expert, but I am doing 3 units of math and am halfway through my HSC course... and this is all pretty basic stuff.

 

[Insomniac55]

Double post, delete.

 

[SnowCold]

It can be either 48/(2(9+3)) or (48/2)(9+3), so both answers are right