48÷2(9+3) =

[IronWing]

Did anyone mention that the correct answer is 2?

 

[zokudu]

Everything to the right of the division symbol is considered the denominator. I see where all the wrong people are coming from, but that just isn't the case. I showed how and why in simple algebra.

But the use of an obelus instead of a / does not mean everything to the right is in the denominator. Also your Algebra only allows the use of the Distributive property because the variable makes it impossible to remove grouping symbols without using the property.

 

[Whoozyerdaddy]

I'm reading it like this:

It's written as 48/2(9+3)
So...

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


48
-----
2(12)


48
------
24


2

 

[zokudu]

I'm reading it like this:

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


so

48
-----
2(12)


48
------
24


2

The use of an obelus instead of a / does not imply this.

 

[Whoozyerdaddy]

The use of an obelus instead of a / does not imply this.

Ganted it's been 20 years since I took a math class but divide is divide

The little divide sign thingy and "/" mean the same thing.

If he'd written it as (48/2)(9+3) then it would be 288

 

[zokudu]

Actually when typing like this then the denominator stuff is never implied. If you wanted the answer to be 2 you would have to write:
48 / [2(9+3)]

You have to physically type a fraction (as you did in your explanation) to get 2 as a result.

 

[Locut0s]

Like I was saying above even math majors are likely to miss this. Only programmers are likely to nail it right away.

 

[SSSnail]

Reading this thread just makes me realize that the lot of you are dumber than my penis, and believe me you, my penis has made some pretty dumb decisions.

 

[Matthiasa]

Like I was saying above even math majors are likely to miss this. Only programmers are likely to nail it right away.

Or programing languages are dumb... 😛
That and they don't imply anything unlike what happens in math. 😛

 

[Locut0s]

Reading this thread just makes me realize that the lot of you are dumber than my penis, and believe me you, my penis has made some pretty dumb decisions.

Again it's usually comp sci people / programmers and the like who deal with order of operation on a day in and day out basis. Even if you study math for a living you could easily mess that up.

 

[SSSnail]

Again it's usually comp sci people / programmers and the like who deal with order of operation on a day in and day out basis. Even if you study math for a living you could easily mess that up.

My penis is pretty good at dividing and it says no, and it does neither.

 

[Suspicious-Teach8788]

Wife has a math degree. She says 2. The brackets are implied around 2(9+3) because of distributive property. It is to be treated as a single term [2(9+3)]

ok well my PhD friend at MIT who's doing math says its 288, so I think I one upped your wife.

 

[repoman0]

48*0.5(9+3)

 

[zokudu]

48*0.5(9+3)

This guy wins multiple internets.

 

[MaxFusion16]

those that insist it's 2 are morons,

the equation as it's presented here equates 288, period, there is no room for doubt.

it would only be 2 if there is another set of brackets []

 

[Cheesetogo]

...

 

[zanejohnson]

order of operations people.

 

[zanejohnson]

my god really?

and this is a smart peoples forum?

 

[Cheesetogo]

Everything to the right of the division symbol is considered the denominator. I see where all the wrong people are coming from, but that just isn't the case. I showed how and why in simple algebra.

Your algebra makes the same assumption that you are making in evaluating the statement to start with.

You see it as

Others see it as

.

I do not see how the distributive property would imply that there are brackets around 2(9+3). The distributive property merely allows you to say that x(a+b)= xa + xb ASSUMING that x is being multiplied by (a+b) in the first place. Assuming that multiplication does not take precedence over division, you should not be multiplying 2 and (9+3) in the first place.

 

[NuclearNed]

One of my 2 majors in college was math, so I consider myself a professional math guy.

I read the Wiki article on order of operations, then I read the references to the article. I think the following paragraph (from one of the references) summarizes the controversy:

http://mathforum.org/library/drmath/view/52582.html

[q]In summary, I would say that the rules actually fall into two
categories: the natural rules (such as precedence of exponential over
multiplicative over additive operations, and the meaning of
parentheses), and the artificial rules (left-to-right evaluation,
equal precedence for multiplication and division, and so on). The
former were present from the beginning of the notation, and probably
existed already, though in a somewhat different form, in the geometric
and verbal modes of expression that preceded algebraic symbolism. The
latter, not having any absolute reason for their acceptance, have had
to be gradually agreed upon through usage, and continue to evolve.[/q]

My interpretation of this paragraph is that the order of operations is still evolving. There are 2 schools of thought, one traditional and one that is more current. Neither is particularly more correct than the other until somehow one or the other is standardized. Until that day happens, I'll go with the "my dear Aunt Sally" method that I was taught in grade school...

...which makes the answer 2

 

[RedRooster]

 

[Drako]

I have a math degree, and the answer is 288 🙂

 

[Cheesetogo]

Bahahaha

 

[repoman0]

One of my 2 majors in college was math, so I consider myself a professional math guy.

I read the Wiki article on order of operations, then I read the references to the article. I think the following paragraph (from one of the references) summarizes the controversy:

http://mathforum.org/library/drmath/view/52582.html

[q]In summary, I would say that the rules actually fall into two
categories: the natural rules (such as precedence of exponential over
multiplicative over additive operations, and the meaning of
parentheses), and the artificial rules (left-to-right evaluation,
equal precedence for multiplication and division, and so on). The
former were present from the beginning of the notation, and probably
existed already, though in a somewhat different form, in the geometric
and verbal modes of expression that preceded algebraic symbolism. The
latter, not having any absolute reason for their acceptance, have had
to be gradually agreed upon through usage, and continue to evolve.[/q]

My interpretation of this paragraph is that the order of operations is still evolving. There are 2 schools of thought, one traditional and one that is more current. Neither is particularly more correct than the other until somehow one or the other is standardized. Until that day happens, I'll go with the "my dear Aunt Sally" method that I was taught in grade school...

...which makes the answer 2

why exactly is there any controversy? multiplication and division are the same operation. division by 2 is multiplication by 0.5, period. pemdas is only valid until you realize this, usually sometime in high school or college. then it turns into "pema", where division is multiplication by 1 over whatever you're dividing by and subtraction is addition by a negative number.

 

[PieIsAwesome]

Order of operations says do everything in parenthesis, then left to right for things of equal precedence. At least its like this in C++.

But does it really matter? This is like an argument over semantics. In alternate-universe America it could be 2, according to their rules. Group operations together and no more confusion.