48÷2(9+3) = ??? - Page 4

monster · 04-15-2011, 12:22 AM

Quote:

Originally Posted by SteveDallas

A. http://blogs.edweek.org/teachers/coa...--forever.html

B. http://www.angrymath.com/2009/03/pem...prejudice.html

C. I blame whoever wrote the equation, because it begs for misinterpretation. Extra parentheses for clarification are never wrong.

D. Why the hell did I open a math thread started by Flint? It's always trouble.

but you believe the answer is......

SteveDallas · 04-15-2011, 12:49 AM

Quote:

Originally Posted by monster

but you believe the answer is......

288.

In spite of MDAS, Multiplication and Division are equal in precedence. Evaluation proceeds from left to right. The use of the 2(..) notation for multiplication is tempting you to treat 2(9+3) as a single unit. 48 / 2 x (9+3), with the multiplication sign written out, seems less ambiguous (though I don't think it is).

Again, it's a screwy example.

skysidhe · 04-15-2011, 12:10 PM

Quote:

Originally Posted by SteveDallas

288.

In spite of MDAS, Multiplication and Division are equal in precedence. Evaluation proceeds from left to right. The use of the 2(..) notation for multiplication is tempting you to treat 2(9+3) as a single unit. 48 / 2 x (9+3), with the multiplication sign written out, seems less ambiguous (though I don't think it is).

Again, it's a screwy example.

yes

HungLikeJesus · 04-15-2011, 12:43 AM

Excel says...

288

I tried it four times.

Maybe they do it different in the old country.

Juniper · 04-15-2011, 12:59 AM

I want to add something to my answer. I've been thinking about it (while cleaning my office - not like I'm obsessing or anything).

My "gut feeling" with this answer was to say it was 2, because of the way it's written. Sometimes I've found on tests you have to figure out what they want for an answer, which may not be what is technically correct. Which of course implies that math may not be as black-and-white as you'd think, that problems are open to interpretation, which is kind of weird, but anyway.

I think that if the intention were to get 288 as an answer, the question would have been written: (48÷2)(9+3) = ??? But because it lacked that one set of brackets, the author of the question wanted us to multiply 9+3 by 2 before dividing 48 by something. I've always felt that a number right next to a bracket implied a sense of urgency. But I still think the correct answer is 288.

And if you read this and rolled your eyes, you have a deeper understanding of why I am an English major.

skysidhe · 04-15-2011, 01:07 AM

good meme

infinite monkey · 04-15-2011, 07:38 AM

This is so why I'm not taking the GRE.

Trilby · 04-15-2011, 08:08 AM

Let's Lynch Flint!

see? That'll fix everything.

Besides, Flint is crazy.

Spexxvet · 04-15-2011, 08:11 AM

Spexxvet · 04-15-2011, 08:12 AM

What if you shuffle the cards on a treadmill while you solve the equation? Huh?

HungLikeJesus · 04-15-2011, 08:16 AM

This is a good problem for an English major. It's analogous to a poorly written sentence; proper punctuation would clear up the meaning.

Juniper · 04-15-2011, 01:51 PM

Quote:

Originally Posted by HungLikeJesus

This is a good problem for an English major. It's analogous to a poorly written sentence; proper punctuation would clear up the meaning.

Precisely! It's the mathematical equivalent of "eats, shoots and leaves."

Cloud · 04-15-2011, 09:19 AM

+1 above.

do math people call parentheses, "brackets" 'cause I still see no brackets in that equation.

thank goodness I slept through three years of algebra so I could stay awake during english

Spexxvet · 04-15-2011, 09:38 AM

Quote:

Originally Posted by Cloud

do math people call parentheses, "brackets" 'cause I still see no brackets in that equation.

No, English people do, apparently.

monster · 04-15-2011, 11:09 AM

Quote:

Originally Posted by Spexxvet

No, English people do, apparently.

correct

04-15-2011, 12:43 AM	#4
HungLikeJesus Only looks like a disaster tourist Join Date: Feb 2007 Location: above 7,000 feet Posts: 7,208	Excel says... 288 I tried it four times. Maybe they do it different in the old country. __________________ Keep Your Bodies Off My Lawn SteveDallas's Random Thread Picker.

04-15-2011, 01:07 AM	#6
skysidhe ~~Life is either a daring adventure or nothing.~~ Join Date: Apr 2006 Posts: 6,828	good meme Attached Images

04-15-2011, 08:08 AM	#8
Trilby Slattern of the Swail Join Date: Jul 2004 Posts: 15,654	Let's Lynch Flint! see? That'll fix everything. Besides, Flint is crazy. __________________ In Barrie's play and novel, the roles of fairies are brief: they are allies to the Lost Boys, the source of fairy dust and ...They are portrayed as dangerous, whimsical and extremely clever but quite hedonistic. "Shall I give you a kiss?" Peter asked and, jerking an acorn button off his coat, solemnly presented it to her. —James Barrie Wimminfolk they be tricksy. - ZenGum

04-15-2011, 08:11 AM	#9
Spexxvet Makes some feel uncomfortable Join Date: Dec 2005 Posts: 10,346	__________________ "I'm certainly free, nay compelled, to spread the gospel of Spex. " - xoxoxoBruce

04-15-2011, 08:12 AM	#10
Spexxvet Makes some feel uncomfortable Join Date: Dec 2005 Posts: 10,346	What if you shuffle the cards on a treadmill while you solve the equation? Huh? __________________ "I'm certainly free, nay compelled, to spread the gospel of Spex. " - xoxoxoBruce

04-15-2011, 12:59 AM	#5
Juniper I know, right? Join Date: Aug 2008 Posts: 1,539	I want to add something to my answer. I've been thinking about it (while cleaning my office - not like I'm obsessing or anything). My "gut feeling" with this answer was to say it was 2, because of the way it's written. Sometimes I've found on tests you have to figure out what they want for an answer, which may not be what is technically correct. Which of course implies that math may not be as black-and-white as you'd think, that problems are open to interpretation, which is kind of weird, but anyway. I think that if the intention were to get 288 as an answer, the question would have been written: (48÷2)(9+3) = ??? But because it lacked that one set of brackets, the author of the question wanted us to multiply 9+3 by 2 before dividing 48 by something. I've always felt that a number right next to a bracket implied a sense of urgency. But I still think the correct answer is 288. And if you read this and rolled your eyes, you have a deeper understanding of why I am an English major.

04-15-2011, 07:38 AM	#7
infinite monkey Person who doesn't update the user title Join Date: Mar 2011 Posts: 13,002	This is so why I'm not taking the GRE.

04-15-2011, 08:16 AM	#11
HungLikeJesus Only looks like a disaster tourist Join Date: Feb 2007 Location: above 7,000 feet Posts: 7,208	This is a good problem for an English major. It's analogous to a poorly written sentence; proper punctuation would clear up the meaning. __________________ Keep Your Bodies Off My Lawn SteveDallas's Random Thread Picker.

04-15-2011, 09:19 AM	#13
Cloud ... Join Date: Feb 2007 Posts: 8,360	+1 above. do math people call parentheses, "brackets" 'cause I still see no brackets in that equation. thank goodness I slept through three years of algebra so I could stay awake during english __________________ "Guard your honor. Let your reputation fall where it will. And outlive the bastards!"

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