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# 48÷2(9+3) = ? watch

• View Poll Results: 48/2(9+3)
2
117
52.47%
288
106
47.53%

1. (Original post by nuodai)
Yes, because using a big font isn't needlessly irritating or anything.

The reason it "could" be equal to either depends on whether the (9+3) is on the numerator or denominator. If this problem were to be interpreted by a computer [EDIT: most computers, depending on whether the programmers have made concessions precisely for this issue], then because computers follow BIDMAS pretty much accurately, what they'll see is:

48÷2×(9+3)

And because of the lack of bracket around 2×(9+3), the computer will interpret this as "take 48, divide it by 2, and then multiply what you get by 9+3", giving the answer 288. This is because, as far as a computer is concerned, "÷2" is the same as "×(1/2)" and then all the multiplications are done sequentially, so you get 48×(1/2)×(9+3).

However, because we're humans, we might think that the (9+3) lies on the denominator of the fraction, in which case what we do is "take 48, work out 2×(9+3) and then divide 48 by that", giving the answer 2. Alternatively, we might think in the same way as the computer, which is how this whole silly debate started.

Personally I think the notation is ambiguous. It's unclear whether the 9+3 should be on the numerator or denominator, and whatever the implicit prescribed rules for this sort of thing are, you could forgive anyone for making a notational error.

However these threads do illustrate why LaTeX is a good idea; far too often people don't make it clear what's on a numerator or denominator, e.g. when people write, say, 1+x/3+x, they might have meant or or a number of other things, and whether they got the notation right or wrong makes no difference to what they meant. So I think future reference to this thread for such people is probably the only good thing to come out of all this.

Sigh. The maths forum is usually so nice.

EDIT: This post might also be useful for:
2. (Original post by Aeschylus)
I've gone with the option of having a girlfriend and a life
doing this maths isnt about having a life, its about not being an absolute retard, which is what this thread starter is.
3. (Original post by wanderlust.xx)
Knowing the more complicated stuff in maths doesn't mean you know the easier stuff.

One of my lecturers knows a hell of a lot about real variable theory but that doesn't mean he can answer any of my quantum questions.
good to know
4. (Original post by goldsilvy)
Where does the second pair of brackets come from? The one in second line? After dealing with (9+3), you're left with 48/2(12), which is the same as 48/2x12 = 24x12 = 288.
It's an imaginary bracket that I put in there to demonstrate "BIMDAS" rather than BIDMAS. I think if in a fraction form it would be much easier to say that it's 288. To be honest, why would a sum need to have in it 48/2? Wouldn't you just know that that's 24 anyway?
5. Bodmass, bidmass ..
6. (Original post by Glutamic Acid)
What the ****?
...Yes, I'm having a slow day.
7. They really need to kill BIDMAS or equivalent and start replacing it with PROPER rules of precendence. It's embaressing how so many here are following it so closely.
8. Have the people that are saying 288 heard of BIDMAS?
Brackets, then indices, then division, then multiplication, then addition, then subtraction.
48÷2(9+3) = 48÷2(12) = 48÷24 = 2
It would be 288 if it was (48÷2)(9+3).
9. (Original post by street.lovin')
it can only be 288 if you put bracket over 48/2 like this >> (48/2)(9+3)

But in the question there is only one bracket >> 48/2(9+3) so calculate stuffs in the bracket first and times it with 2 and divide 48 by the result..

Why are so many people thinking its 288.

Stupid.
At first I thought it was 2 as well, but if we did it the other way we'd get 288. Brackets would have helped indeed.
10. ^^^ just type it in your calculator its 288

however if its a fraction with the 2(9+3) on the bottom its 2.
11. (Original post by joshgoldman)
Have the people that are saying 288 heard of BIDMAS?
Brackets, then indices, then division, then multiplication, then addition, then subtraction.
48÷2(9+3) = 48÷2(12) = 48÷24 = 2
It would be 288 if it was (48÷2)(9+3).
NO.

Multiplication and Division are THE SAME PRECEDENCE. How many times do I have to say this???

When 2 operations are the same precedence you work LEFT TO RIGHT.
12. (Original post by Vav123)
^^^ just type it in your calculator its 288

however if its a fraction with the 2(9+3) on the bottom its 2.
That's because the fraction operation on your calculator puts the denominator in hidden brackets.
13. (Original post by King-Panther)
BODMAS B=Brackets O=Order D=Division M=Multiply A=Add S=Subtract, that is the order of BODMAS. Bracket first (9+3) = 12. Now we have 48/2(12), when there are two things (can't remember the correct term) together and no symbol, its automatically multiply. So that will be 48/2x(12). So what is next according to Bodmas? D comes before M, so we do the division next, 48/2=24. Now we have 24(12) or 24x(12) which equals 288.
BODMAS (Or BIDMAS) works in groups as highlighted. Brackets first, then Order/Indices, then Divide OR multiply (they are the same type of operation simply inversely proportional thus for example it doesn't matter if you do (8x2)/4 or (8/4)x2) and then Add or Subtract... Just thought I'd put that out there
14. (Original post by nuodai)
The reason it &quot;could&quot; be equal to either depends on whether the (9+3) is on the numerator or denominator. If this problem were to be interpreted by a computer [EDIT: most computers, depending on whether the programmers have made concessions precisely for this issue], then because computers follow BIDMAS pretty much accurately, what they'll see is:

48÷2×(9+3)

And because of the lack of bracket around 2×(9+3), the computer will interpret this as &quot;take 48, divide it by 2, and then multiply what you get by 9+3&quot;, giving the answer 288. This is because, as far as a computer is concerned, &quot;÷2&quot; is the same as &quot;×(1/2)&quot; and then all the multiplications are done sequentially, so you get 48×(1/2)×(9+3).

However, because we're humans, we might think that the (9+3) lies on the denominator of the fraction, in which case what we do is &quot;take 48, work out 2×(9+3) and then divide 48 by that&quot;, giving the answer 2. Alternatively, we might think in the same way as the computer, which is how this whole silly debate started.

Personally I think the notation is ambiguous. It's unclear whether the 9+3 should be on the numerator or denominator, and whatever the implicit prescribed rules for this sort of thing are, you could forgive anyone for making a notational error.

However these threads do illustrate why LaTeX is a good idea; far too often people don't make it clear what's on a numerator or denominator, e.g. when people write, say, 1+x/3+x, they might have meant or or a number of other things, and whether they got the notation right or wrong makes no difference to what they meant. So I think future reference to this thread for such people is probably the only good thing to come out of all this.

Sigh. The maths forum is usually so nice.

EDIT: This post might also be useful for:
Quotes

Ahhhhh, I got it.

I was jsut explaining on how I would calculate it when I saw it.

Didn't think too deep about how the brain and the calcualtor works.

Thank you.

PS* I would still answer 2. :P
15. (Original post by StephenP91)
The way I see it is this:

People are seeing it like this 48(9+3)/2 and some I seeing it like this 48/2(9+3).

(Original post by street.lovin')
it can only be 288 if you put bracket over 48/2 like this &gt;&gt; (48/2)(9+3)

But in the question there is only one bracket &gt;&gt; 48/2(9+3) so calculate stuffs in the bracket first and times it with 2 and divide 48 by the result..
Why do anything outside the bracket in any thing other than left to right order?
16. (Original post by Jallenbah)
No. There is an unambiguous order of preference. Brackets, Indices, then Multiplication and Division, then Addition and Subtraction.
If the precedence is equal, i.e. Multiplication and Division, then you go left to right.

Always.
There is no debate.
Try writing equations like that in your exam and see if your lecturers agree with you that its completely acceptable and unambiguous notation. Let me know how that goes.
17. (Original post by Jallenbah)
NO.

Multiplication and Division are THE SAME PRECEDENCE. How many times do I have to say this???

When 2 operations are the same precedence you work LEFT TO RIGHT.
So he's wrong. So what? Are you going to devote your life to correcting people who are wrong on the internet?
18. (Original post by joshgoldman)
Have the people that are saying 288 heard of BIDMAS?
Brackets, then indices, then division, then multiplication, then addition, then subtraction.
48÷2(9+3) = 48÷2(12) = 48÷24 = 2
It would be 288 if it was (48÷2)(9+3).
19. Oh my god. 17 pages. And I'm so getting in on this.

The answer is 288. Check Wikipedia (source of all knowledge) if you don't believe me but essentially division is just multiplication of the reciprocal. Therefore the calculation can be expressed as 48 x 1/2 x (9+3) which equals 288.

These mnemonics may be misleading, especially if the user is not aware that multiplication and division are of equal precedence, as are addition and subtraction.
http://en.wikipedia.org/wiki/BODMAS

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