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On April 08 2011 07:13 thesideshow wrote:Those using PEMDAS/BEMDAS, Do you do what's in the parenthesis/brackets first? 48÷2(9+3) 48÷2(12) 24(12) 288 Or get rid of the parenthesis/brackets first? 48÷2(9+3) 48÷2(12) 48÷24 12 + Show Spoiler +Quick thought: If you do the first method, aren't you doing the division before properly dealing with the brackets, thus violating PEMDAS/BEMDAS?
your second one is just wrong, once you've done the parenthesis you do it from left to right. The problem presented in this thread is the ÷ sign is easily interpreted in different ways and there's a lack of proper brackets to show the correct order.
edit: you dont need to fully eliminate the parenthesis because you can rewrite it as
48÷2(9+3)
48÷2(12)
48÷2*12
24*12
288
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On April 08 2011 07:09 MasterOfChaos wrote:Show nested quote +On April 08 2011 07:02 JinDesu wrote:On April 08 2011 07:01 Retgery wrote:
I see the mistake now, some people see it as (48 )/2 (9+3) and if 48÷2 is seen as a fraction then the answer comes out to 288, but what some (me included) saw was 48÷[2(9+3)] comes out to 2. This question is a bitch...
Yep, it's the assumption that the division sign automatically sets everything to the right in a bracket. Writing it out on a board or paper would help. The division sign does exactly what it's supposed to. Divide the left number by the right number. The question isn't about the division sign IMO. It's about the omitted multiplication sign. I argue that an omitted multiplication sign is different from an explicit multiplication sign.
brackets/parentheses is a multiplication sign. the only time you can completely neglect a multiplication sign altogether (no brackets either) is when you are multiplying a variable with a constant, variable, or function (you can write 2*x as 2x but you cant write 2*8 as 28 obviously but you can write it as 2(8))
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United States24772 Posts
On April 08 2011 07:13 thesideshow wrote:Those using PEMDAS/BEMDAS, Do you do what's in the parenthesis/brackets first? 48÷2(9+3) 48÷2(12) 24(12) 288 Or get rid of the parenthesis/brackets first? 48÷2(9+3) 48÷2(12) 48÷24 12 + Show Spoiler +Quick thought: If you do the first method, aren't you doing the division before completely dealing with the brackets, thus violating PEMDAS/BEMDAS?
Dealing with the brackets as the first part of evaluation a math expression only means evaluating what is inside the parentheses.... not multiplying the parentheses by other things.
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On April 08 2011 07:13 thesideshow wrote:Those using PEMDAS/BEMDAS, Do you do what's in the parenthesis/brackets first? 48÷2(9+3) 48÷2(12) 24(12) 288 Or get rid of the parenthesis/brackets first? 48÷2(9+3) 48÷2(12) 48÷24 12 + Show Spoiler +Quick thought: If you do the first method, aren't you doing the division before completely dealing with the brackets, thus violating PEMDAS/BEMDAS?
I thought it was 2, but the answer is 288. 12 is wrong no matter how you cut the cookie though.
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On April 08 2011 07:13 iCCup.Raelcun wrote:
The only people who are dropping my jaw in this thread are the people who are refusing to acknowledge that it's a trick because of multiple ways of interpretation.
People with little education often believe that "knowledge" is about simple rules and laws, rather than a body of shared thoughts, ideas, and converging (as well as diverging) practices.
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On April 08 2011 07:09 MasterOfChaos wrote:Show nested quote +On April 08 2011 07:02 JinDesu wrote:On April 08 2011 07:01 Retgery wrote:
I see the mistake now, some people see it as (48 )/2 (9+3) and if 48÷2 is seen as a fraction then the answer comes out to 288, but what some (me included) saw was 48÷[2(9+3)] comes out to 2. This question is a bitch...
Yep, it's the assumption that the division sign automatically sets everything to the right in a bracket. Writing it out on a board or paper would help. The division sign does exactly what it's supposed to. Divide the left number by the right number. The question isn't about the division sign IMO. It's about the omitted multiplication sign. I argue that an omitted multiplication sign is different from an explicit multiplication sign.
As someone else showed in this thread; wolframalpha is with you to some extend. Implicit (with omitted sign) multiplication of variables is treated stronger than explicit division. http://www.wolframalpha.com/input/?i=48/2a, a=(9+3)
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On April 08 2011 07:13 GizmoPT wrote:Show nested quote +On April 08 2011 07:12 YokaY wrote:On April 08 2011 07:07 micronesia wrote:
I am not aware of any difference between / and the other division sign... they both mean the same thing to me. Can anyone point me to a reference that says otherwise? They don't mean anything different. It's just what they create visually and how they affect peoples assumptions. One looks like this A / / / / BC vs. A÷BC vs. A/BC in my university if they put A÷BC its A÷(B*C) so i dont know why people saying people that get 2 are dumb :\
If the explicitly say A divided by B times C is A/(B*C), then that seems quite off to me.
It's so much different writing it out on the computer like that than actually drawing it out.
Someone with super awesome drawing skills should do it!
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United States24772 Posts
On April 08 2011 07:16 Uhnno wrote:Show nested quote +On April 08 2011 07:13 thesideshow wrote:Those using PEMDAS/BEMDAS, Do you do what's in the parenthesis/brackets first? 48÷2(9+3) 48÷2(12) 24(12) 288 Or get rid of the parenthesis/brackets first? 48÷2(9+3) 48÷2(12) 48÷24 12 + Show Spoiler +Quick thought: If you do the first method, aren't you doing the division before completely dealing with the brackets, thus violating PEMDAS/BEMDAS? I thought it was 2, but the answer is 288. 12 is wrong no matter how you cut the cookie though.
If you look carefully you will see that he simply made a mistake typing the final answer... not difficult to miss and no need to point out that it is wrong. Unless you think 48/24=12 lol
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8th grader here, is this really considered hard?
Parentheses
Exponents
Multiplication
Division
Addition
Subtraction.
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Just like people learn rules of english grammar in middle and elementary school (don't end a sentence with a preposition!) which don't actually capture the natural use of language, rules like PEMDAS don't always capture the natural reading of mathematical expressions. The expression x/yz is most naturally read as equivalent to the disambiguated x/(yz) and not (xz)/y. Someone who intended to write the latter as x/yz would either be daft or perverse.The fact that the most common and convenient notation for division is the bar with the dividend on top and divisor on the bottom, on which this particular ambiguity is impossible, is one reason for this.
All this, of course, has nothing to do with math but with the interpretation of notation. For both reasons, everybody who's blathering "lolol I can't believe tl is so bad at math I am ashamed of the human race" should take a good long look at themselves in a mirror and then smash their face into it.
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On April 08 2011 07:13 thesideshow wrote:Those using PEMDAS/BEMDAS, Do you do what's in the parenthesis/brackets first? 48÷2(9+3) 48÷2(12) 24(12) 288 Or get rid of the parenthesis/brackets first? 48÷2(9+3) 48÷2(12) 48÷24 12 + Show Spoiler +Quick thought: If you do the first method, aren't you doing the division before completely dealing with the brackets, thus violating PEMDAS/BEMDAS?
Doing what's in the brackets 'gets rid' of them. E.g. 3 + (1*3) = 3 + (3) = 3 + 3.
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On April 08 2011 07:16 Uhnno wrote:
48÷24
12
I sincerely hope that was a typo
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I always learned even up through Uni that
48÷2(12)
It would be WRONG to treat this as 24 x 12
That you should always distribute to 48 / 24 FIRST.
If you do 48÷2(12x), it is incorrect always to go 24(12x), and you must do 48/(24x)
Is this not always the proper approach?
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On April 08 2011 07:07 micronesia wrote:
I am not aware of any difference between / and the other division sign... they both mean the same thing to me. Can anyone point me to a reference that says otherwise?
![[image loading]](http://imgur.com/u6sTZ.jpg)
Basically I use / symbol when scrawling on a single line of loose leaf, to lazily mean x / (y+z) instead of x/y+z, which is more proper.
EDIT: Because of this, I got 2 initially. I was also confused because I could see the poll results before voting so I kept double checking and getting more confused lol
PS GooN PosT WooT
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United States24772 Posts
On April 08 2011 07:17 Usyless wrote:
All this, of course, has nothing to do with math but with the interpretation of notation. For both reasons, everybody who's blathering "lolol I can't believe tl is so bad at math I am ashamed of the human race" should take a good long look at themselves in a mirror and then smash their face into it.
This is why I was going to originally close this thread... but I guess it's better to address the issue than sweep it under the rug.
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On April 08 2011 07:17 VarpuliS wrote:
8th grader here, is this really considered hard?
Parentheses
Exponents
Multiplication
Division
Addition
Subtraction.
I think the intent of the re-opened thread is to be more of a language-arts thing. Read the thread, and see why this is considered a good troll question.
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Didn't vote as I'm late to the party but I want to throw in my 0.02 kroner.
In 9th grade I learned that to resolve the parenthesis in 2(9+3), you do 2*9 + 2*3, leaving 48/24 = 2.
Through the power of the internets i learned about PE(DM)(AS): (9+3) = 12, 48/2*12 = 288.
By the way, I think the common way of writing divisions is, for example 10 over 5, or
10
----
5
which is written 10/5 on computers for simplicity. This would have been an easy question if it used / instead of whatever the fuck that other thing is.
48
---------
2(9+3)
This is where I think people get confused...
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The way I looked at it was:
1) 48÷2(9+3)
2) 48÷2(12) = 48÷2*12
3) 24*12
4) 288
Between steps 1 and 2, after completing the 9+3 in the parentheses, they essentially drop, and aren't a part of the equation anymore, because they don't demand anything be done first anymore (by PEMDAS, or whatever). Thus, it's just a matter of going left to right from step 2, with division/multiplication being interchangeable in the acronym
edit: Raelcun beat me to it at the top o the page 
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Oh I get my mistake now. It's simple. You go by regular BEDMAS rules it's just I forgot that when doing the Multiply and Division part you do it on a Left to Right manner so after you get:
48/2(12)
Your supposed to divide 48/2 first not the 2(12) part first.
Simple mistake though, I don't feel extremely terrible for not getting it initially.
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On April 08 2011 07:18 Mailing wrote:
I always learned even up through Uni that
48÷2(12)
It would be WRONG to treat this as 24 x 12
That you should always distribute to 48 / 24 FIRST.
If you do 48÷2(12x), it is incorrect always to go 24(12x), and you must do 48/(24x)
Is this not always the proper approach?
In Uni terms writing it as
48÷2(12)
is completely wrong as it's ambiguous notation. So that logic is very very flawed
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EPT
