48÷2(9+3) = ???

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  • frankenbeemer
    replied
    When you add 9 + 3 you get 12, then you are done with the parenthetical element. At that point, you return to the left because multiplication and division are equal operators. I have yet to see the rule which states that 2(some operation) is different from 2*(some operation) or 2 x (some operation).

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  • imsotyerred
    replied
    PEMDAS fucking rules

    2 nitwits

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  • frankenbeemer
    replied
    Please add 4.65517241 to the poll.

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  • frankenbeemer
    replied
    Let's see:

    Get rid of the parenteses, 48/29+3.

    = 4.65517241

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  • reelizmpro
    replied
    Originally posted by rwh11385
    That's not how it was written. You're making assumptions when you write it as 48/(2(12)). If that were the case, it should have been written 48/(2(9+3)), not 48/2(9+3). NOWHERE does it state that your way is the proper way to read it. Almost all cases of distributive property does not have more than the three variables, so it's your assumption that it ought to be performed as a whole before the rest, but that's not right.

    In every order of operations lesson, you should do what is in the parentheses first, and then treat the multiplication as just that.. but not necessarily before any other of the same level of operator.

    Simplify 48/2(9+3) into 24(9+3). And what is the result??? You simplified it into dividing by 12 when it is supposed to be multiplying.
    Look you are solving it wrong. Stop going left to right. It is NOT 48/2 multiplied by (9+3). You said it yourself...Parentheses first remember? 48/(18+6) OR 48/2(12). Why are the parentheses still there? because the 2 is distributed INTO them as it is part of the expression "2(9+3)". Then parentheses are no longer needed after adding the (18+6) = 24 OR 2 multiplied by 12 all UNDER 48. ONLY then are the parentheses no longer needed. Write it down on paper 48 OVER 2(9+3). Get rid of the parentheses first and tell me what you get.

    By the way. Even if you simplify...it's still 24 OVER (9+3). This is allowed because the 2 was factored out but the rest of the expression is still DIVIDED into the numerator. The significance of the 2 outside of the parentheses is that it is a FACTOR of what's inside. Again, write it all out. 48 OVER 2(9+3).

    The Left to right business is really elementary and is the last rule to follow with all operations being equal. Doesn't really have a place here with this type of problem. Parentheses first...and you get rid of them through distributing (multiplying) and adding before you do anything else.
    Last edited by reelizmpro; 04-09-2011, 12:45 PM.

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  • Sean
    replied
    288.

    Oh ya, and put rob on that poll dammit!

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  • rwh11385
    replied
    Originally posted by reelizmpro
    WHAT? Okay, look... stop using *. This operation occurs in the distributive property of algebra. It's understood. To properly type the expression online or in a calculator: 48/(2(12)). If you want, you could simplify 48/2 and get 24/12 = 2. If you do it on paper, it'll make more sense.
    That's not how it was written. You're making assumptions when you write it as 48/(2(12)). If that were the case, it should have been written 48/(2(9+3)), not 48/2(9+3). NOWHERE does it state that your way is the proper way to read it. Almost all cases of distributive property does not have more than the three variables, so it's your assumption that it ought to be performed as a whole before the rest, but that's not right.

    In every order of operations lesson, you should do what is in the parentheses first, and then treat the multiplication as just that.. but not necessarily before any other of the same level of operator.

    Simplify 48/2(9+3) into 24(9+3). And what is the result??? You simplified it into dividing by 12 when it is supposed to be multiplying.

    Leave a comment:


  • frankenbeemer
    replied
    Originally posted by reelizmpro
    WHAT? Okay, look... stop using *. This operation occurs in the distributive property of algebra. It's understood. To properly type the expression online or in a calculator: 48/(2(12)). If you want, you could simplify 48/2(12) and get 24/12 = 2. If you do it on paper, it'll make more sense.
    Can you provide a link to this "understood" property? I don't understand it.

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  • reelizmpro
    replied
    Originally posted by rwh11385
    Nowhere does it say that distributive property means the statement cannot be broken up. Order of operations has you do inside the parentheses and then after look for MD operations, but nowhere does it say that this multiplication is magically more important than the division to the left of it - whether or not there used to be a parens attached to it.

    It should be 48/2*12.

    If you wanted to distribute it out, then could rewrite as (48/2*9+48/2*3)

    Example:
    2(9+3) = 18 + 6 = 24

    What if you wanted to take one third of that?
    1/3*2(9+3)=(2/3*9+2/3*3)=8

    And one half of that?
    1/3(9+3)=(9/3+3/3)=4 ..... NOT 1/(27+9) = 1/36
    WHAT? Okay, look... stop using *. This operation occurs in the distributive property of algebra. It's understood. To properly type the expression online or in a calculator: 48/(2(12)). If you want, you could simplify 48/2(12) and get 24/12 = 2. If you do it on paper, it'll make more sense.

    Leave a comment:


  • rwh11385
    replied
    Originally posted by reelizmpro
    Did you 288 guys even read what I wrote?

    Here's more proof the answer is 2.

    "The distributive property of multiplication CLEARLY states that the 2(9+3) is an entire statement and CANNOT be broken up. 2(9+3) follows the distributive property which can be rewritten as (2*9+2*3). Let me repeat the 2 outside of the parenthesis follows the distributive property of multiplication and must be factored and simplified before performing any other operations on it. You do NOT compute this expression from left to right until you use Algebra to simplify the statement 2(9+3).

    So this can be rewritten as:
    48 / (2*9 + 2*3)

    Which leaves us with

    48 / 24 = 2

    Answer = 2.

    Lastly for those using Google or any other online calculator. These do not understand many theorems or properties so you must explicitly explain what you mean. There is a difference between 48 / 2 * (9+3) and 48 / 2(9+3). The first notation reads 48 / 2 * 1(9+3) while the second reads 48 / (2*9+2*3). Be very careful with your signs."

    As a EE who has worked with many scientific calculators and programs like MATLAB, etc. The guy I quoted above is right. Have to be careful of signage and calculators are very picky on how you input it.
    Nowhere does it say that distributive property means the statement cannot be broken up. Order of operations has you do inside the parentheses and then after look for MD operations, but nowhere does it say that this multiplication is magically more important than the division to the left of it - whether or not there used to be a parens attached to it.

    It should be 48/2*12.

    If you wanted to distribute it out, then could rewrite as (48/2*9+48/2*3)

    Example:
    2(9+3) = 18 + 6 = 24

    What if you wanted to take one third of that?
    1/3*2(9+3)=(2/3*9+2/3*3)=8

    And one half of that?
    1/3(9+3)=(9/3+3/3)=4 ..... NOT 1/(27+9) = 1/36
    Last edited by rwh11385; 04-09-2011, 10:54 AM.

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  • reelizmpro
    replied
    Originally posted by frankenbeemer
    Distributive property: The sum of two numbers times a third number is equal to the sum of each addend times the third number. For example 4 * (6 + 3) = 4*6 + 4*3


    Where does it indicate this special case where I must ignore the order of operations?
    It follows the order of operations. Parentheses first. 2(9+3) can either be 2(12) OR ((2*9 + 2*3))...agreed? Parentheses are still there until you multiply through to get 24...agreed? Don't convert the () into *, the multiplication occurs through the distributive property. This is the key. This is why you multiply first. Work it out on paper, the old fashioned way to eliminate this left to right business.
    Last edited by reelizmpro; 04-09-2011, 10:57 AM.

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  • LivingLegend06
    replied
    It's 288.

    Everyone who doesn't think so is probably a woman because they suck at math. You hear that guys, I just called you all girls.

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  • frankenbeemer
    replied
    Distributive property: The sum of two numbers times a third number is equal to the sum of each addend times the third number. For example 4 * (6 + 3) = 4*6 + 4*3


    Where does it indicate this special case where I must ignore the order of operations?

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  • ck_taft325is
    replied
    Why.

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  • reelizmpro
    replied
    Did you 288 guys even read what I wrote?

    Here's more proof the answer is 2.

    "The distributive property of multiplication CLEARLY states that the 2(9+3) is an entire statement and CANNOT be broken up. 2(9+3) follows the distributive property which can be rewritten as (2*9+2*3). Let me repeat the 2 outside of the parenthesis follows the distributive property of multiplication and must be factored and simplified before performing any other operations on it. You do NOT compute this expression from left to right until you use Algebra to simplify the statement 2(9+3).

    So this can be rewritten as:
    48 / (2*9 + 2*3)

    Which leaves us with

    48 / 24 = 2

    Answer = 2.

    Lastly for those using Google or any other online calculator. These do not understand many theorems or properties so you must explicitly explain what you mean. There is a difference between 48 / 2 * (9+3) and 48 / 2(9+3). The first notation reads 48 / 2 * 1(9+3) while the second reads 48 / (2*9+2*3). Be very careful with your signs."

    As a EE who has worked with many scientific calculators and programs like MATLAB, etc. The guy I quoted above is right. Have to be careful of signage and calculators are very picky on how you input it.
    Last edited by reelizmpro; 04-09-2011, 10:38 AM.

    Leave a comment:

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