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48÷2(9+3) = ? watch

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

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    (Original post by Jallenbah)
    If it was ambiguous and language dependent, then moving to a new language would be a nightmare in which you have to flood your code with brackets.
    If in doubt, bracket, as any C/C++ programmer will tell you (since the language's precedence choices for things like logical operations and shifts are, frankly, bizarre).

    The order of precedence IS universally accepted and where precedence is equal, it is also universally accepted that you go left to right.
    Exponentiation generally goes right-to-left; try typing 2^2^3 into Wolfram-Alpha and you'll see.

    Again, most experienced programmers don't rely on left-to-right ordering if they can avoid it.
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    My point is, is that if somebody wrote 1 +x / 3 + x, I'd know what they meant, but I'd still tell them to be more clear, as it could be interpreted differently, quite easily. I would argue that it's more important to be mathematically correct than to know what somebody means, as obviously if it's written correctly this would imply that somebody again knows what it means. If it's written correctly in the first place, then there need not be any confusion.

    I understand the point that we define notation to suit us, but it's basic notation that should only have one interpretation, if it's written correctly. For example, I'd agree with your e^it, because the person reading this would know what the expression was referring to, and would have some knowledge of the context. However, I don't think different interpretations should exist when basic maths notation is used, such as in this case. I'd say that the question in this case 'should' have one answer, but it doesn't because it can be interpreted in different ways. I'd argue that this is wrong.

    I think latex is good .
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    Your right,

    =48/2(9+3) (brackets first)
    =48/2(12) (remove the brackets by multiplying out)
    =48/24 (divide)
    =2

    The 2 is seperate from the 48 as there is no symbol between 48/2 and (9+3)
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    So, 2 it is?
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    (Original post by DanielleT192)
    So, 2 it is?
    No, read DFranklin's discussion of it in post 374. That is a pretty good summing up.
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    (Original post by little_wizard123)
    I understand the point that we define notation to suit us, but it's basic notation that should only have one interpretation, if it's written correctly. For example, I'd agree with your e^it, because the person reading this would know what the expression was referring to, and would have some knowledge of the context. However, I don't think different interpretations should exist when basic maths notation is used, such as in this case. I'd say that the question in this case 'should' have one answer, but it doesn't because it can be interpreted in different ways. I'd argue that this is wrong.
    What's your point? That the notation system should be improved upon? All well and good, but no matter how good notation gets, maths is such a big subject that some statements will still be ambiguous. This is where mathematical convention comes in. That's not foolproof either though, since sometimes (as here), 2 conflicting mathematical conventions occur in the same statement. In that situation, you have to resort to asking the author. (OP? any comments? :P)

    As far as the programming side is concerned, certainly different languages will interpret it differently, since (as is generally agreed) the statement is an ambiguous one. The solution is, again, "ask the author". ie. reject the input, which is clearly faulty (if this question occurs from correct input, then there's something wrong somewhere else in the program).
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    (Original post by Good bloke)
    No, read DFranklin's discussion of it in post 374. That is a pretty good summing up.
    I'm not too bothered anymore. The discussions went on for too long lol.
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    If I saw 1 + x / 1 - x, I'd assume it was (1 + x) / (1 - x). But only because the BODMAS reading is 1 + (x / 1) - x = 1 which is just weird. So I'd accept that the person who wrote it was being a bit lazy with the brackets.

    If I saw 1/2y, I'd insist on clarification. But the quadratic formula: blah/2a, I would be fine with because I already know what it means. Ditto with e^it even though something like 2^4x isn't that clear to me.

    In this example, I'd ask for clarification. But of course, this is a smart arse example and we aren't going to get any. So the best bet is to use the rules that we're all supposed to agree on. I've never seen implied multiplication taking precedence (I assume it's also supposed to come before powers too?) but it does seem sensible. The rules probably do need tweaking to keep up with usage but for now, they are what they are.
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    Lets start with the initial notation, before we do everyone seem to agree (9+3) = 12.

    48÷2(9+3) = 48÷2(12)

    How does that read to you?

    For me it reads, 48 divided by 2 times 12, which is equivalent to 48 divided by 24, which is 2

    or does it read

    48 divided by 2, times 12 (Notice the comma). Which gives 288.
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    The question is ambiguous, the answer could be 2 or 288.

    now 8÷4÷2=?

    1 or 4?
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    (Original post by Farmer Giles)
    Lets start
    "Lets start"? Seriously? 20 pages of argument and you start your post with "Lets start"?

    EDIT: Just realised how dickish that sounds. Sorry. But seriously, you're not exactly treading new ground here; at least read SOME of the most recent comments.
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    I honestly thought this was originally a TSR joke....
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    http://forum.bodybuilding.com/showth...hp?t=133415833 Even before reading this I would have gone for 288. And even google agrees which is the best.

    As some have said previously, BODMAS doesn't matter after we have done our (9+3) calculation. So we work from left to right. But even if we use the BODMAS order even though the division doesn't take precedence over the multiplication, you will get 288.

    So it is 288 either way, unless you take (9+3) in the denominator which should have extra brackets when written in the straight line.
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    (Original post by Haddock3)
    What's your point? That the notation system should be improved upon?
    To an extent, yes! If the general consensus that BIDMAS doesn't work in this case (I'd argue it does) then it should be made clearer. It's division and multiplication; it's basic stuff. Half the time on TSR you can't understand what the hell is being asked.

    Edit: I'd not even describe it as a change in notation. It's something basic taught in primary school that should only have one interpretation.

    (Original post by SsEe)
    If I saw 1 + x / 1 - x, I'd assume it was (1 + x) / (1 - x). But only because the BODMAS reading is 1 + (x / 1) - x = 1 which is just weird. So I'd accept that the person who wrote it was being a bit lazy with the brackets.

    If I saw 1/2y, I'd insist on clarification. But the quadratic formula: blah/2a, I would be fine with because I already know what it means. Ditto with e^it even though something like 2^4x isn't that clear to me.

    In this example, I'd ask for clarification. But of course, this is a smart arse example and we aren't going to get any. So the best bet is to use the rules that we're all supposed to agree on. I've never seen implied multiplication taking precedence (I assume it's also supposed to come before powers too?) but it does seem sensible. The rules probably do need tweaking to keep up with usage but for now, they are what they are.
    This. When it's ambiguous, as it would appear to be, we apply the rules that we 'should', which should result in only one answer.
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    (Original post by smiffhead)
    You are again missing the point...
    -nothing to do with how the numerator and denominator are grouped in a fraction,
    -the point is that ANY multiplication implied by juxtaposition is not just a multiplication, it involves a coefficient,
    -which by definition is joined to the bit after it (multplicand or variable or whatever), and must treated as together!

    answer's 2
    You've just made up that distinction. Coefficients are exactly the same as multiplication. Source plz.
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    http://www.wolframalpha.com/input/?i=48%2F2*x+at+x%3D12

    its 288!

    No, seriously I don't know.

    First thought was 2.

    After reading (and realising division was before multiplication in BODMAS) i thought 288.

    Now apparently these differ according to wolframalpha:

    1/2*x and 1/2x - this makes sense to me, and now I am thinking 2 again... I think BODMAS was just some wierd thing they invented for school that just doesn't apply...
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    Okay most of you don't know what your talking about .


    The answer is not 2 or 288.

    Sum: 48/2(9+3)= 3.43 (rounded to 1 dp)

    Method: 9+3 = 12
    12+2 = 14

    48 / 14 = 3.428....

    lol owned
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    (Original post by Haddock3)
    Sorry, skipped the beginning of this particular sub-convo, so may be missing your point, but what IS your point? Sure, if we WERE using vertical fractional notation this question would be clearer. But we're not.
    That was my point.
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    (Original post by mangoh)
    Okay most of you don't know what your talking about .


    The answer is not 2 or 288.

    Sum: 48/2(9+3)= 3.43 (rounded to 1 dp)

    Method: 9+3 = 12
    12+2 = 14

    48 / 14 = 3.428....

    lol owned
    I want to have a huge go at you for this, but a) it couldn't be more clearly a troll, and b) that would break the rule of a certain mod who said not to have a go at someone simply because you don't like their answer. (can't remember who it was :P)
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    (Original post by Haddock3)
    I want to have a huge go at you for this, but a) it couldn't be more clearly a troll, and b) that would break the rule of a certain mod who said not to have a go at someone simply because you don't like their answer. (can't remember who it was :P)
    lol I can take it , it's a forum to discuss... of course listen to what the mod says but if you politely suggest why I am wrong then it should be fine.

    BUT... I doubt u can as I am clearly right.
 
 
 
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