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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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    BODMAS
    brackets: (9+3)=12
    Division: 48/2=24
    Multiplication last: 24 x 12 = 288
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    According to wolfram alpha it is 288 and since they are also never wrong, the answer has to be 288:

    http://www.wolframalpha.com/input/?i...B72%289%2B3%29

    It is like writing it this way:



    24 (9+3)
    24 (12)
    288
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    It depends.

    11 pages on this. Jesus.

    Guys it's sunny outside.

    Get up and get down and get outside.
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    The misc is strong
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    Ok let me just make this very clear.

    Multiplication and Division have EQUAL precedence
    BIDMAS is an oversimplification of operator precedence taught to childeren. In reality, Multiplication and Division are equal, as are Addition and Subtraction.
    What this means is that when you encounter a sum with them both, you do it left to right.

    In our case:
    48/2(9+3)
    Brackets first
    48/2(12) = 48/2*12
    Now we do NOT do multiplication before division here - we do it LEFT TO RIGHT. To make that easier with brackets -
    (48/2)*12
    Now it's simple
    24*12 = 288

    There is NO ambiguity. It is blatently clear and there is no debate to be had. If you think the answer is anything other than 288, you are wrong. This is not a matter of opinion.
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    (Original post by ily_em)
    288! 288! 288!
    Cue for the opposition fans to come in with:

    Come on you twooos! Come on you twooos!
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    The brackets definitely need to be solved first. That's the rule with order of operations (BEMDAS or BEDMAS - since D and M are interchangeable; source: http://en.wikipedia.org/wiki/Order_o...ions#Mnemonics)

    So, this means we can re-write the given equation as 48 ÷ 2 x 12
    From here, doing either the division first or the multiplication first are both acceptable, depending on which format of the order of operations you follow. In some formats, multiplication comes before division, in others, multiplication comes after division.

    So you could either have: 48 ÷ 24 = 2
    or
    24 x 12 = 288

    Both 2 and 288 are correct, but the "right" answer ultimately depends on which format of the order of operations is used (both are equally acceptable).
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    wolfram says 288, but I still think it is two, BIDMAS and all that jazz

    http://www.wolframalpha.com/input/?i...B72%289%2B3%29
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    (Original post by Awesomesauce)
    BODMAS
    brackets: (9+3)=12
    Division: 48/2=24
    Multiplication last: 24 x 12 = 288
    Right answer, wrong reason.

    BODMAS is misleading unless you remember it properly.

    The rule actually goes
    Brackets
    then powers Of (or Other)
    then Division AND Multiplication (same precedence)
    then Addition AND Subtraction (same precedence)

    However there is an additional rule, that you parse operators of the same precedence from left to right, so you do do the division first in this case
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    (Original post by Jallenbah)
    Ok let me just make this very clear.

    Multiplication and Division have EQUAL precedence
    BIDMAS is an oversimplification of operator precedence taught to childeren. In reality, Multiplication and Division are equal, as are Addition and Subtraction.
    What this means is that when you encounter a sum with them both, you do it left to right.

    In our case:
    48/2(9+3)
    Brackets first
    48/2(12) = 48/2*12
    Now we do NOT do multiplication before division here - we do it LEFT TO RIGHT. To make that easier with brackets -
    (48/2)*12
    Now it's simple
    24*12 = 288

    There is NO ambiguity. It is blatently clear and there is no debate to be had. If you think the answer is anything other than 288, you are wrong. This is not a matter of opinion.
    this this oh god this.
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    (Original post by summer_l)
    The brackets definitely need to be solved first. That's the rule with order of operations (BEMDAS or BEDMAS - since D and M are interchangeable; source: http://en.wikipedia.org/wiki/Order_o...ions#Mnemonics)

    So, this means we can re-write the given equation as 48 ÷ 2 x 12
    From here, doing either the division first or the multiplication first are both acceptable, depending on which format of the order of operations you follow. In some formats, multiplication comes before division, in others, multiplication comes after division.

    So you could either have: 48 ÷ 24 = 2
    or
    24 x 12 = 288

    Both 2 and 288 are correct, but the "right" answer ultimately depends on which format of the order of operations is used (both are equally acceptable).
    The same wikipedia page you linked to tells you you are wrong (look at the last paragraph before Mnemonics section.

    With operators of the same precedence (ie / and *), you work left to right, always

    Thus the answer is 288. No "depends"
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    (Original post by summer_l)
    From here, doing either the division first or the multiplication first are both acceptable, depending on which format of the order of operations you follow.
    :no: That way ambiguity lies. Mathematics doesn't do ambiguity.
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    (Original post by arabcnesbit)
    It depends.

    11 pages on this. Jesus.

    Guys it's sunny outside.

    Get up and get down and get outside.
    Speak for yourself it's chucking it down here
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    (Original post by HistoryRepeating)
    Its been explained to you several times what the rules are and how they apply.

    Which part do you disagree with - the rule that multiplication and division are of equal precedence, the rule that you deal with equal precedence operators left to right, or that these rules apply to give 288?

    Please explain your thinking.

    PS: I have a feeling its a wooly "doing the multiplication first just FEELS more normal"
    Well I do agree with what you are saying but I'd personally take the unclearly written 48÷2(9+3) to be 48/2(9+3). If it were 288 it would've been (48÷2)(9+3) in separate brackets to show that the both of those are multiplying together but by putting the 2 right in front of the (9+3) shows to me that you work that out first and then do the calculation from left to right as 48÷24 to give you 2.

    Again, it's the way the questioner has presented it with.

    Your whole argument on the BODMAS palava is still being applied to the way me and others have done it.
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    (Original post by Ree69)
    Yes but 48÷2(9+3) and 48/2 x (9+3) are the same thing. BIDMAS clearly explains that division is before multiplication. Hence 288.

    I'm quite worried about the number of people who thought this was 2...
    It is two...what you guys are missing out is the fact that multiplications without a multiplication sign (such as ab, or 3y, 2x) should be done first - this is not included in any variant of bodmas.
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    It's worth noting that its largely irrelevant because no-one past GCSE level uses the divide sign. This is the reason we use either:

    48
    _______

    2(9+3)

    or

    48/2 . (9+3)

    depending on which we mean.
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    (Original post by DanielleT192)
    Well I do agree with what you are saying but I'd personally take the unclearly written 48÷2(9+3) to be 48/2(9+3). If it were 288 it would've been (48÷2)(9+3) in separate brackets to show that the both of those are multiplying together but by putting the 2 right in front of the (9+3) shows to me that you work that out first and then do the calculation from left to right as 48÷24 to give you 2.

    Again, it's the way the questioner has presented it with.

    Your whole argument on the BODMAS palava is still being applied to the way me and others have done it.
    You are right when you take 48÷2(9+3) to be 48/2(9+3)
    These are identical in meaning.

    You are wrong on the bold bit. You dont multiply out brackets before applying the left-to-right rule - why would you?

    Again you are just basing this on your gut instinct (which is sadly wrong) rather than the actual notation standards.

    By the way do you interpret 1/2x as half x or 1/(2x) ?
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    (Original post by smiffhead)
    It is two...what you guys are missing out is the fact that multiplications without a multiplication sign (such as ab, or 3y, 2x) should be done first - this is not included in any variant of bodmas.
    That isn't true. Please cite any source.

    Multiplications using a heavy dot, or a dash, get done first. Multiplicands are dealt with normally.
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    (Original post by HistoryRepeating)
    What on EARTH does the order that various calculators parse symbols have to do with which way is correct.

    In any case, if we are playing the calculator game:
    The equation gives 2 on a TI-82, but 288 on a TI-83.

    Oh look....

    The correct order of precedence is left to right for equal priority operators. This is not just "technically" correct but how it is done, correctly, in practice.

    as I've said however, normally you would not use the divide symbol, instead using fractional notation, and the vertical position of the elements of the equation would make things clear (vertical position effectively acts like parentheses, similarly to the way the top bar of a route symbol does)

    You're funny.

    I'm guessing you didn't read my post properly.

    I'm not arguing about rules of precedence. I hope we both understand them very well. I'm talking about conventions adopted by manufacturers of calculators.

    Am I allowed to do that?
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    (Original post by py0alb)
    It's worth noting that its largely irrelevant because no-one past GCSE level uses the divide sign. This is the reason we use either:

    48
    _______

    2(9+3)

    or

    48/2 . (9+3)

    depending on which we mean.
    Wrong that it is irrelevent because writing it as:
    48/2(9+3)
    causes exactly the same debate (and is still 288)
 
 
 

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