48÷2(9+3) = ???
 

Just a simple test of your math skills. What is the correct answer, and why?

2

because it's the right answer

(48/2)(9+3) = 144

48/(2(9+3)) = 2

Any other boring 3rd grade arithematic questions?

Oh yeah, 48/2=24 (duh), 24x12=288

UT wins!

2

?

288. The reason is order of operations

No, terms inside brackets precede division.

exactly. you did the division first. brackets first.

no i did the parens first and then, from left to right, division and then multiplication

brackets (parentheses to yanks) first: 9+3 = 12.

brackets are mutiplied by 2 = 24

.......

logically, how can 48 divided by anything be 288? I still say 2

the multiplication by 2 is part of the brackets phrase. Otherwise it would be written 48 / 2 * (9+3)

it is written that way.

brackets first 9+3 = 12

then division 48/2 = 24

then multiplication 24 * 12 = 288

I do not see any brackets.

if you then multiply it by 12

You don't do multiplication/division from left-to-right like it's prose. Multiplication comes first regardless of where it is. Assume that the parentheses are done first, so now we have:

48 ÷ 2 x 12

That is the same as

48 x (one-half) x 12

Your way puts the 12 as a denominator in the fraction, which it wouldn't be unless there were also parentheses around the (2 x 12).


The mnemonic they taught us in grade school was My Dear Aunt Sally: multiplication, division, addition, then subtraction.

Multiplication AND division are done first...

(a) No, it isn't written that way
(b) you're relying on Wikipedia

Google and Wolfram Alpha agree with me.

there is no left to right in math. when there are both multiplication and division, multiplication goes first. that's why 2(whatever) means 2 * whatever. There is no division equivalent because it isn't needed because multiplication happens first

they're wrong.

Order of operations: PEMDAS

Parentheses, equations, multiplication, division, addition, subtraction.

However, multiplication/division and addition/subtraction are equal.

Therefore, the answer is 24 x 12 = 288

Slinking back into the shadows now.

you are contradicting yourself. If they were equal, one wouldn't be before the other on the order of operations. Generally, there is no difference, but this is the illustration of why there is an order of ops that puts mult before div.

At what point do I point out my BSc (honours) in math? I don't care what wikipedia says that google fetches up and other shit..... The answer is 2.

Yes but you got that degree off the back of a cereal box and I claim victory.

PEMDAS is easier to say than PEDMSA but I guess you could do PEDMAS or BEDMAS (for brackets) and it wouldn't really matter. That's the way I was taught, back in the ice age.

Maybe I ought to ask my kids. I'm really not smarter than a 5th grader. :)

Or in my case, 7th grader and 9th grader . . . OMG, the 9th grader asked me for math homework help and I Could Not Do It. Algebra. Polynomials. :::scream:::

No, I didn't, and PEMDAS backs me up. Claim all the victory you like, you're still wrong.

Juniper, it does matter, that's why it's PEMDAS and nothing else. It just doesn't matter very often.

Math is not left to right -maybe that's why left-handers are good at it? :p:

288, just because I plugged it into my calculator as written.

Maybe my BSCS and three decades of computer programming will count for something?

you could outprogram me in a heartbeat (although my BSc was a joint honours with Computer Science) ...it just won't get you anywhere in math if the main hits on a google search are too simplistic. ;)

well done.

Hopefully,

The answer would be two if the notation was written differently. ..but it's not

right.

tired now.. will give my defense in the morning.

the answer is two

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......

It needs more brackets to be two.

I stand by Occam's razor in this.

Excel says...

288

I tried it four times.

Maybe they do it different in the old country.

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.

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. :thepain:

good meme

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

Let's Lynch Flint!

see? That'll fix everything.

Besides, Flint is crazy.

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

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

+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

No, English people do, apparently.

the ANSWER is cock

What is in that vagina, Alex?

beeep beeep beeep beeep

Yes, monkey?

What is "in the mouf" Alex.

correct

so, the "brackets" in the order of operations refers to parentheses? what do English people call brackets?

and why would you want to multiply, when the equation clearly reads, "forty-eight divided by . . . "

very confusing! am frankly glad that I don't know the answer and don't need to know the answer!

I agree with the folks that have already said that this is an ambiguously written problem.

As a thread starter and fuel for conversation, it's pretty good.

As a example arithmetic question, it is poorly written, if the intent was to help the student learn about the order of operations.

In Flint's opening post, he says

Others have given the (pretty easy) justification for why "2" is the answer; I've seen justifications for "288". Which is correct? Well, that depends on the author, doesn't it? Well, Flint? What is the correct answer, and why?

I could just as easily say the correct answer is "???" because it says so right there in the thread title. That's "correct", isn't it? I could say "the correct answer is what the teacher says is the correct answer" or "whatever gets me an A on this test". Those answers are equally valid given the level of ambiguity here. What if we're assuming this equation is written in base 10 but it's really base 12? Then the "correct" answer would be just as uncertain given the way it's written, but it wouldn't be 2 or 288. After all, (skyshide), since we should make the fewest assumptions, assuming base 12 is equally likely as base 10, and both sufficiently explain the data already given.

So, as a plain arithmetic problem, I say the answer is 2.

If it's not plain arithmetic, then that's an entirely different problem.

Oh Lordy, Miss O'Hara, Tara is all but deserted -the yankees have done taken all the darkies and trampled all the cotton. Looks like you're just going to have to do the work for yourself. Ain't no-one to pump your gas now or -Lord forbid you should blister your poor dainty fingers- type "brackets" into Wikipedia and see what comes up.

since feeling is first
who pays any attention
to the syntax of things
will never wholly kiss you;

wholly to be a fool
while Spring is in the world

my blood approves,
and kisses are a better fate
than wisdom
lady i swear by all flowers. Don't cry
- the best gesture of my brain is less than
your eyelids' flutter which says

we are for each other; then
laugh, leaning back in my arms
for life's not a paragraph

And death i think is no parenthesis

--e.e. cummings

Possum Pbweed.:p:

It may be intended to teach the left to right convention.

I'd like "names for male animals" for $1,000.

not sure where the southern/yankee thing comes in?

Rather than relying on Wikipedia so you can turn around and belittle the poster for that, as above, I turned to Websters Dictionary, which defines brackets as:

"either of the pair of signs [ ], or sometimes < > used to enclose a word or words inserted as for explanation, quantities to be taken as a single quantity, etc."

parentheses are not mentioned.