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## View Poll Results: ？

1. 40 26.85%
9. 99 66.44%
Hard to say. 8 5.37%
Voters: 149. You may not vote on this poll

Oct 12th, 2012, 03:43 AM   #181
Novichok
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Re: 6÷2（2+1）=？

Quote:
 Originally Posted by égalité No, all the steps there are true in both versions of order of operations in question. I'm not totally sure what you mean by "dependent on the semantics!"
Nevermind. I just realized where I was mistaken. Your proof is flawless.
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 Oct 12th, 2012, 09:16 AM #182 Sam L Sunset, Moonrise, Winter     Join Date: Oct 2001 Location: Australia Posts: 31,661 Re: 6÷2（2+1）=？ I said 9 but I can see how someone can get 1. Can someone tell me why it's not 1 again? Thanks. I can't be bothered reading 13 pages of this. __________________ Have I not my talent left? Can I not, like Monica, Serena, Marion, acquire for myself what you would never have given me? - Bel Grugnito Diva Pas de Quatre: Swan Lake, Giselle, The Nutcracker, Coppélia
 Oct 12th, 2012, 09:35 AM #183 Sam L Sunset, Moonrise, Winter     Join Date: Oct 2001 Location: Australia Posts: 31,661 Re: 6÷2（2+1）=？ I thought the best way to prove that 9 was right was this: 2(2+1) = 2 x (2+1) just like 2(3) = 2 x 3. Right? Therefore, it is 6 ÷ 2 x 3 = 9 To say the answer is 1 would mean the question is written 6÷(2(2+1)). Where do the extra brackets come from? Where? __________________ Have I not my talent left? Can I not, like Monica, Serena, Marion, acquire for myself what you would never have given me? - Bel Grugnito Diva Pas de Quatre: Swan Lake, Giselle, The Nutcracker, Coppélia
 Oct 12th, 2012, 10:31 AM #184 Sam L Sunset, Moonrise, Winter     Join Date: Oct 2001 Location: Australia Posts: 31,661 Re: 6÷2（2+1）=？ OMG there are Youtube clips on this: __________________ Have I not my talent left? Can I not, like Monica, Serena, Marion, acquire for myself what you would never have given me? - Bel Grugnito Diva Pas de Quatre: Swan Lake, Giselle, The Nutcracker, Coppélia
 Oct 12th, 2012, 01:11 PM #185 Super Dave Senior Member     Join Date: Dec 2005 Posts: 24,870 Re: 6÷2（2+1）=？ __________________ Elena Baltacha 1983-2014
 Oct 12th, 2012, 01:24 PM #186 JJ Expres Senior Member     Join Date: Sep 2007 Posts: 3,580 Re: 6÷2（2+1）=？ http://www.wolframalpha.com/input/?i=6%2F2%282%2B1%29 just use Wolfram, however you type it with or without * it gives the same answer, it's 9...
 Oct 12th, 2012, 07:30 PM #187 zigga Senior Member     Join Date: Aug 2011 Posts: 4,063 Re: 6÷2（2+1）=？ This is too easy Here is one more interesting math problem: how much is 0.9 periodic (so 0.9999...)? I just find it amusing that it can be proven that it equals 1 __________________ Maria Sharapova Ivanović | Dementieva | Hercog | Kvitova | Robson
 Oct 12th, 2012, 07:50 PM #188 pov Senior Member     Join Date: Feb 2008 Posts: 13,550 Re: 6÷2（2+1）=？ hmmm . my original posted answer was 1. Based on multiplication before division. Rewriting though 6x1/2x3 =9 so However according to Wolfram Alpha "implied multiplication without parentheses precedes division" so that makes the answer 1. The overall issue here is a poorly written problem but given its parameters the correct reading, by the accepted standards I know and those I've re-checked, is 6÷ (2（2+1）) __________________ “Nonviolence means avoiding not only physical violence but also internal violence of spirit. You not only refuse to shoot a man, but you refuse to hate him.” – MLK
Oct 12th, 2012, 08:03 PM   #189
pov
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Re: 6÷2（2+1）=？

one more source:
American Mathematical Society (AMS)

Quote:
 "multiplication indicated by juxtaposition is carried out before division." Thus, in general, for any variables a, b and c, we would have a/bc = a/(bc) (assuming, of course, that b and c are nonzero).
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 Oct 12th, 2012, 08:05 PM #190 Nicolás89 Senior Member     Join Date: Jul 2006 Posts: 18,737 Re: 6÷2（2+1）=？ Lol It is 9. __________________ LEGEND. Nicole. Caro. Aga. Sloane. Taylor.
 Oct 12th, 2012, 08:16 PM #191 delicatecutter Senior Member     Join Date: Jul 2006 Location: The periphery Posts: 29,578 Re: 6÷2（2+1）=？ Jesus Christ on a cross, egalite is a mathematics professional. Take his word for it. __________________ Rybáriková ♥ Ivanović ♥ S.Williams ♥ A.Radwańska ♥ Kerber ♥ Kvitová ♥ Schmiedlová ♥ Jovanovski Govortsova ♥ Kanepi ♥ Federer ♥ del Potro ♥ Cetkovská ♥ Giorgi ♥ Cibulková ♥ Pavlyuchenkova Suicide Champion: 2013 Miami; 2012 Doha; 2011 Dubai; 2010 Indian Wells, Bad Gastein; 2008 Melbourne, New Haven, Prague; 2007 Toronto PAW Champion: 2012 Tokyo, Moscow; 2011 Roland Garros; 2010 Bali, Portoroz TT Doubles Champion (with Djezonfly): 2012 Melbourne, 2011 Estoril My Twitter
Oct 12th, 2012, 10:15 PM   #192
pov
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Re: 6÷2（2+1）=？

Quote:
 Originally Posted by égalité Of course there is. Mathematicians don't establish rules like these unless they're essential. Here's why it matters for the problem in this thread: Multiplication of real numbers is associative: (ab)c=a(bc). Take four nonzero integers a,b,c,d and multiply: a times b/c times d. By associativity, (ab/c)d=a(b/cd). But interpreting these expressions in the same manner that is used to achieve an answer of 1, we get (ab/c)d=(abd)/c, and a(b/cd)=ab/(cd). These are not equal. If we mess around with order of operations, multiplication becomes non-associative.
Perhaps you should contact the AMS (see above) since according to them a/bc is to be interpreted as a/(bc)

Either way, your "proof" is flawed. There is nothing in the problem (or either answer) that countermands the associative property. I'll let you figure it out.
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Oct 12th, 2012, 10:24 PM   #193
JJ Expres
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Re: 6÷2（2+1）=？

Quote:
 Originally Posted by zigga This is too easy Here is one more interesting math problem: how much is 0.9 periodic (so 0.9999...)? I just find it amusing that it can be proven that it equals 1
x=0.99999999999999999999999999999....
10x=9.99999999999999999999999999999......
10x-x=9
9x=9
x=1

 Oct 12th, 2012, 10:38 PM #194 Sammo Senior Member     Join Date: Feb 2009 Location: Serious & agressive floor Posts: 24,391 Re: 6÷2（2+1）=？ It's 9. Trust me, I'm a 1st grade Chemical Engineering student __________________ MIRJANA "MLB Da MVP" LUCIC-BARONI | SAM STOSUR ☯ | MARTINA HINGIS ♚ | DANIELA HANTUCHOVA ✯ | OLGA PUCHKOVA ❤ | MADISON KEYS ☢ | MARTINA NAVRATILOVA (because fuck you that's why) "Selfishness is not living as one wishes to live, it is asking others to live as one wishes to live."
 Oct 12th, 2012, 10:59 PM #195 Miracle Worker Senior Member     Join Date: Oct 2010 Location: Universe Posts: 25,167 Re: 6÷2（2+1）=？ WTF is （? If （ = () the result should be 9. 6:2x(2+1)= 3x3=9 __________________ The Brainless Pusher Ernests Gulbis, Marin Cilic, John Isner Gilles Simon, Nicolas Almagro, Tommy Haas, Jack Sock Kimiko Date Krumm, Tomas Berdych, Michail Youzhny, Daniel Brands Elena Dementieva, Julia Cohen, Anna Chakvetadze