48÷2(9+3) = ????

[Hamtaro]

I was right in my assumption about TIF's Off-Topic, at least :thumbup:

[Distracted]

I risk looking like a complete idiot for asking this, but what if you put it in a fraction? I see why the answer is 288, but when you put the exercise as a fraction it's a different story, right?

 

So purely out of interest, is it different when it's put in a fraction? Or is a fraction mathematically different from a division, since I always thought they were the same. It's just for the sake of knowledge here.

 

[spoiler=What I'd do with a fraction]

48

-----------

2(9+3)

 

24

---------

(9+3)

 

24

----

12

 

2

--

1

 

Or alternatively:

 

48

---------

2(9+3)

 

48

---------

2(12)

 

48

----

24

 

2

--

1

 

 

So am I just doing it completely wrong?

[Iamdan]

.

[Gbpackers31]

I risk looking like a complete idiot for asking this, but what if you put it in a fraction? I see why the answer is 288, but when you put the exercise as a fraction it's a different story, right?

 

So purely out of interest, is it different when it's put in a fraction? Or is a fraction mathematically different from a division, since I always thought they were the same. It's just for the sake of knowledge here.

 

[spoiler=What I'd do with a fraction]

48

-----------

2(9+3)

 

24

---------

(9+3)

 

24

----

12

 

2

--

1

 

Or alternatively:

 

48

---------

2(9+3)

 

48

---------

2(12)

 

48

----

24

 

2

--

1

 

 

So am I just doing it completely wrong?

 

Well actually the (9+3) is not in the denominator to begin with. If you substitute (9+3) for x, you'd get 48/2x. This, however, is equivalent to 48x/2 because it goes by basic order of operations. You divide first and then multiply. So you divide the 2 into 48 and then multiply by x (which would put the x in the numerator). If you wanted to write the equation how you have, you'd need parentheses on the 2x (or brackets on the 2(9+3)). So using x, it would be 48/(2x) and back to the original equation, 48/[2(9+3)].

[Riku3220]

Also, just searched for the thread title and about 20 identical threads came up.

 

I just did the same thing. It's amazing how many people on the internet don't know how to do basic math and then try to justify that the right answer is 2. With how it's written, it can only be 288, no ifs', and's, or but's about it.

Because some people were taught with PEMDAS which puts Multiplication before Division and Addition before Subtraction. This is why GEMA is superior.

[RpgGamer]

48÷2(9+3)

48/ 2(12)

48/24

2

 

 

Oddly in my head it came out to 4, but I do see why I'm wrong in either case.

[doomy]

We were taught that it went either multiplication or division depending on which came first.

 

And the fraction mentioned before doesn't work because its really:

48 / 2 * (9+3)

which is the same as

48 * 12 / 2

 

so you'd have the *(9+3) on the top

[Freakyhair]

I did a maths a level and i got 2.

 

 

:'(

[Orpheus]

The left to right thing isn't true, so you need more brackets.

 

My girlfriend does a math degree and she says that there isn't enough information in that question to answer it properly - brackets to prioritize the division or multiplication.

 

You wouldn't come across something like this in a real math problem afaik because it would have a definite answer with brackets.

 

Heh, is that so? In any case, it seems most of us get 288. And maths are incredibly stupid in this case.

[Will H]

I'm pretty sure that it's 288 following BIDMAS, but the syntax of the question is poor. It should read (48/2)(9+3)=. When you express equations in text, you have to be really rigorous with the brackets.

 

Honestly, one of the first rules of maths, don't screw up the syntax when you're asking a question. It's better to have redundant parts than be ambiguous.

 

And if all else fails, stick it in Wolfram Alpha.

[indy500fan]

The answer is definitely 288, but sadly I did get 2 the first time as well (just doing it quick in my head).

[Assume Nothing]

Brackets Indices Division Multiplication Addition Subtraction

 

Hmm, you're right.

 

EDIT - Talking of trollmath, could someone explain why this doesn't work?

 

[Nenga]

Also, just searched for the thread title and about 20 identical threads came up.

 

I just did the same thing. It's amazing how many people on the internet don't know how to do basic math and then try to justify that the right answer is 2. With how it's written, it can only be 288, no ifs', and's, or but's about it.

Because some people were taught with PEMDAS which puts Multiplication before Division and Addition before Subtraction. This is why GEMA is superior.

PEMDAS is fine, it's just that some people forget that in the original explanation (whenever PEMDAS is taught) that Multiplication and Division / Addition and Subtraction are on the same "tier".

With PEMDAS all you're really taught is do do exponents and inside parentheses first, after that the problem reads normally from left to right. Keeping in mind, unless the problem says otherwise, parentheses around a number means to multiply.

 

So it's

 

48/2 = 24

24 *(9+3)

24*12 = 288.

 

PEMDAS works fine.

[obfuscator]

Yeah I did the multiplication first. Makes sense though.

[doomy]

Brackets Indices Division Multiplication Addition Subtraction

 

Hmm, you're right.

 

EDIT - Talking of trollmath, could someone explain why this doesn't work?

 

I'm not sure if this is right or not, but the second last line is pretty much saying 2*0 = 1*0, and the last step is dividing 0 out from both sides?

[Assume Nothing]

Brackets Indices Division Multiplication Addition Subtraction

 

Hmm, you're right.

 

EDIT - Talking of trollmath, could someone explain why this doesn't work?

 

I'm not sure if this is right or not, but the second last line is pretty much saying 2*0 = 1*0, and the last step is dividing 0 out from both sides?

 

Ah, there we go. I just followed what they did and didn't spot that because x = a, x - a = 0

[Juhnie]

The reason people are getting 2 as the answer from their calculators is in the way the calculator processes the problem. It seems to cut the syntax in terms which it will process one by one in the order of operations. DISCLAIMER: Just something I thought up. Nothing official or such :P

 

If you write in 48/2(9+3), some calculators will understand the 2(9+3) a single term with parentheses, ranking the whole term top tier in the order of operations (due to the precense of parentheses) and processes it like this:

 

48/2(9+3)

48/2(12)

48/24

2

 

before moving on with the calculation. If you write in 48/2*(9+3), however, the calculator separates the (9+3) as a separate term and processes it like this to remove the parentheses:

 

48/2*(9+3)

48/2*12

24*12

288

 

I tried this out with my Casio CFX-9850GB PLUS. The result:

 

48/2(9+3) = 2

48/2*(9+3) = 288

 

Agree with Will_H, the syntax is horrible.

[dsavi]

Interesting, I tried it on some different calculators and got different answers:

 

My desktop calculator (gnome-calculator): 2 Edit: When I typed in 48/2*(9+3) it was 288.

PHP ( print 48/2*(9+3); ): 288

Python ( print(48/2*(9+3)) ): 288

C: 288

[spoiler=(Program)]

#include <stdio.h>

int main(void)
{
       int i = 48/2*(9+3);
       printf("i is %i\n", i);
       return 1;
}

 

 

 

I would assume that the calculator would be more reliable, seeing as it's, you know, a calculator. But apparently not.

[Orpheus]

In any case, this problem is not clear enough in terms of what's going with what, even with BIDMAS, PEMDAS, GEMA (what the [bleep] is this). It's not clearly defined how to do this problem correctly. It's still 288 unless brackets/more parentheses say otherwise.

[Riku3220]

In any case, this problem is not clear enough in terms of what's going with what, even with BIDMAS, PEMDAS, GEMA (what the [bleep] is this). It's not clearly defined how to do this problem correctly. It's still 288 unless brackets/more parentheses say otherwise.

GEMA is:

 

Grouping

Exponents

Multiplication and division

Addition and subtraction

[iamcoool11]

This is how I see it:

[spoiler=My solution]48/2(9+3)

First do distributive property:

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

48/24

2

 

At least I think it's right...

I'm pretty sure that the distributive property ignores PEMDAS, and comes before it. :???:

Edit: If I am wrong, feel free to correct me.

[The Observer]

I got 288 using the order of operations.

[Hamtaro]

This is how I see it:

[spoiler=My solution]48/2(9+3)

First do distributive property:

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

48/24

2

 

At least I think it's right...

I'm pretty sure that the distributive property ignores PEMDAS, and comes before it. :???:

Edit: If I am wrong, feel free to correct me.

Distributive property doesn't take precedence in a monomial equation. Because there are no X-terms, the entire equation is one term. The answer is in spoiler tags in the first post btw.

[iamcoool11]

This is how I see it:

[spoiler=My solution]48/2(9+3)

First do distributive property:

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

48/24

2

 

At least I think it's right...

I'm pretty sure that the distributive property ignores PEMDAS, and comes before it. :???:

Edit: If I am wrong, feel free to correct me.

Distributive property doesn't take precedence in a monomial equation. Because there are no X-terms, the entire equation is one term. The answer is in spoiler tags in the first post btw.

I'm still confused. I learned it as always being first. I don't know, I'm just not quite getting it. :oops:

[K4ylan]

This is how I see it:

[spoiler=My solution]48/2(9+3)

First do distributive property:

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

48/24

2

 

At least I think it's right...

I'm pretty sure that the distributive property ignores PEMDAS, and comes before it. :???:

Edit: If I am wrong, feel free to correct me.

Distributive property doesn't take precedence in a monomial equation. Because there are no X-terms, the entire equation is one term. The answer is in spoiler tags in the first post btw.

I'm still confused. I learned it as always being first. I don't know, I'm just not quite getting it. :oops:

 

Think of the parenthesis as a multiplication sign. So, it would be 48/2×12 --> 24×12 --> 288