Solve 48

[JonathanVP]

Typical 5th grade math, I guess no one is smarter than a 5th grader.

[Nayos]

So what do you say to the evidence earlier that distributive multiplication does indeed have a higher order-of-operations presidence than other multiplication?

I say

(light heartedly, of course)

[Stetson]

Typical 5th grade math, I guess no one is smarter than a 5th grader.

It is? I don't recall having a detailed discussion on the presidence of distributive multiplication versus standard multiplication in my 5th grade class. Also those who take the grade school PEMDAS a bit too literally can find themselves in trouble.

If I ever saw an equation written in the format of this one on an exam, I would ask the professor for clarification as to whether (9+3) were in the numerator or the denominator. Unless it was an intentional tricky question on a somewhat obscure presidence rule that seems pretty reasonable to me.

I also would not be surprised to see marks taken off of my work if I were to answer with an equation in this format, rather than in a much clearer fraction form.

[zman982]

48?2(9+3) = 288

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

:cool:

[Nayos]

It is? I don't recall having a detailed discussion on the presidence of distributive multiplication versus standard multiplication in my 5th grade class. Also those who take the grade school PEMDAS a bit too literally can find themselves in trouble.

If I ever saw an equation written in the format of this one on an exam, I would ask the professor for clarification as to whether (9+3) were in the numerator or the denominator. Unless it was an intentional tricky question on a somewhat obscure presidence rule that seems pretty reasonable to me.

I also would not be surprised to see marks taken off of my work if I were to answer with an equation in this format, rather than in a much clearer fraction form.

I must admit, I'm not too familiar with the precedence of the distributive property in the order of operations, do you have any links to anywhere I can read about it?

By the way, what did you think the answer was?

[Stetson]

I must admit, I'm not too familiar with the precedence of the distributive property in the order of operations, do you have any links to anywhere I can read about it?

By the way, what did you think the answer was?

LeeDogg's post on the second page: http://www.purplemath.com/modules/orderops2.htm (It's the 5th green equation).

At first I thought the answer was 288. By the order of operations I've been taught, the 2(9+3) becomes 2*12, and then you do multiplication and division in the same step from left to right. The other way to look at it is that 2(9+3) is a factoring of (18+6), and the rule about distributive presidence would confirm that.

My position though is still that the original equation is ambiguous.

48/[(2(9+3)] is a much better way to write it if you intend the answer to be 2.

48(9+3)/2 is a much better way to write it if you intend the answer to be 288.

[Orange Battery]

Basically the answer depends on what rule you use. There is no universal way of calculating an equation that has not been configured using a universal format.

[Stetson]

Basically the answer depends on what rule you use. There is no universal way of calculating an equation that has not been configured using a universal format.

Agreed 100%

It's first and foremost a formatting issue. There is more than one reasonable way to interpret that equation into a more standard format.

[Versanis]

I'll assume the answer is in fact 288.

Based on that logic, then I will let X = (9+3).

In order for 288 to be the correct answer, the equation becomes 48/2*X = 24*X = 288.

Apply this to a generic algebraic example now, such as X/3X.

This is easily solvable as 1/3.

According to the above example, it would become X/3*X = X?/3.

I've never seen single line algebra done this way. It is excessively convoluted.

[Glen]

LeeDogg's post on the second page: http://www.purplemath.com/modules/orderops2.htm (It's the 5th green equation).

At first I thought the answer was 288. By the order of operations I've been taught, the 2(9+3) becomes 2*12, and then you do multiplication and division in the same step from left to right. The other way to look at it is that 2(9+3) is a factoring of (18+6), and the rule about distributive presidence would confirm that.

My position though is still that the original equation is ambiguous.

48/[(2(9+3)] is a much better way to write it if you intend the answer to be 2.

48(9+3)/2 is a much better way to write it if you intend the answer to be 288.

The distributive property precedence is the way I read it as well, so I would have come up with 2 as the answer with the formula as provided. It's been quite a while since I took math, but I really don't think this is as ambiguous as some have stated here as the distributive rules clearly apply.

[leedogg]

My answer would be 2.

Not because multiplication takes precedence over division.

My reason is summarized here >

Therefore,

48?2(9+3) = 2

48?2*(9+3) = 288

This is because I understand an algebraic statement 2x to be equal to 2(x), and this takes priority over regular multiplication and division. Therefore, 9?2x is equivalent to 9?2(x) which gives me 4.5 / x, instead of 4.5(x).

To further support the 2 answer, I think a key factor here is that the distributive law of multiplication does NOT work for division

The Distributive Law does not work for division:

Example:

24 / (4 + 8) = 24 / 12 = 2, but

24 / 4 + 24 / 8 = 6 + 3 = 9

http://www.mathsisfun.com/associative-commutative-distributive.html

So therefore per the distributive law of multiplication only the 2 can be distributed and since Parenthesis come first, the expression (2x9 + 2x3) needs to be calculated FIRST, before it can be divided into 48.

Using the wording from that site, I believe this expression would read as 48 divided by the sum of 2 lots of 9 plus 2 lots of 3.

[Nayos]

The distributive property precedence is the way I read it as well, so I would have come up with 2 as the answer with the formula as provided. It's been quite a while since I took math, but I really don't think this is as ambiguous as some have stated here as the distributive rules clearly apply.

Yeah this is what I think now. Although, 20 minutes ago I didn't

I've been reading up on multiplication by juxtaposition which apparently should take precedence over any other multiplication or division

If that's the case then 2(9+3) should be evaluated first.

If I put the equation as it's written into my calculator (Ti-89) then I get 288. However, if I substitute the 9+3 for x and the 2 for y and input 48/y(x) then it uses this juxtaposition rule and gives me

If you substitute the numbers back in then you get

So I'm still not sure, but I'm swaying towards 2.

[soniqstylz]

#include <iostream>
using namespace std;

int main()
{
cout << 48 / 2 * (9+3);

return 0;
}

288

lulz.

I'm thinking 2, but I'm now letting facebook decide.

[Hardcore Til I Die]

Solve 48?2(9+3)

post answers and why :p

BODMAS

Brackets

Order (^ / to the power of)

Division

Multiplication

Addition

Subtraction

Therefore:

(9+3) = 12

48 ? 2 = 24

12*24 = 288

[XerXis]

288, without a doubt

[fhpuqrgrpgvirzhpujbj]

Typing this into C++ or C# or python etc is useless because you are inserting a * in so the 'juxtaposition rule' won't take effect. Adding a multiplication symbol changes the equation.

[Nayos]

Typing this into C++ or C# or python etc is useless because you are inserting a * in so the 'juxtaposition rule' won't take effect. Adding a multiplication symbol changes the equation.

Exactly.

[tanjiajun_34]

(48 ? 2) * (9 + 3) = 288

Because Google says so. :laugh:

[capr]

what field are you working in?

[leedogg]

do people not friggin read?

The expression is 2(9+3)

not (9+3)

So parentheses first is (2 x 9 + 2 x 3) divided into 48

[Nayos]

do people not friggin read?

The expression is 2(9+3)

not (9+3)

So parentheses first is (2 x 9 + 2 x 3) divided into 48

:)

[b0nker]

BODMAS?

9+3=12

2*12=24

48?24=2

So 2? :unsure:

I've soo got this all wrong, right?

[ToneKnee]

Surely the 4chan threaded ended in blood after this.. haha

[Rigby]

[Syanide]

do people not friggin read?

The expression is 2(9+3)

not (9+3)

So parentheses first is (2 x 9 + 2 x 3) divided into 48

Brackets first :p I can't believe this thread is still going on, especially after the first reply got it right.

Let's see what we have:

48:2*(9+3)

We do brackets first

48:2*(12)

no need for brackets anymore

48:2*12

once each of the operations are of the same level (and multiplication and division are the same level operations), you just do it left to right

48:2*12 = 24*12 = 288

/thread