48÷2(9+3) = ????

[wiZe]

This thread is making me sad actually. The people who are the most confident about their answer are the most incorrect.

I wonder how you'll feel once you realize you fall into this group. That is...if you take the time to read through this thread and realize the answer is not 2.

 

[M.H.C.]

so '÷' is not equal to '/'?

No. Enter both into a scientific calculator and you will get two different answers.

48÷2(9+3) is asking you to take 48 over 2(9+3) in which you will get 48/24 which equals 2.

48/2(9+3) is asking you to put 48/2 and multiply it by (9+3) which you get 24 multiplied by 12 which equals 288.

Guaranteed.

 

[cbm_redux]

You already solved the parentheses.

2(12) = 2 * 12

I think that I know what these idiots are doing. In a problem like 2(x+y) you would distribute the 2 because you can't add the unlike terms. These numskulls are misapplying that rule to a simple arithmetic problem where you can easily simplify the like terms inside the grouping symbol, then clear the multiplication and division from left to right.

Had I not seen this thread, I wouldn't have guessed that some many people would get it wrong.

 

[Djmarkxr7]

^^^^^

This guy gets it. For those who have forgotten, a division sign indicates a numerator and a denominator--like a fraction. for those who want to give multiplication and division equal footing (left to right), simplify this FRACTION and tell me your answer.....there is NO WAY you will ever get 288.

[/end thread] and that's all folks....all of the 'teachers' talking about 288, you should be fired

Nope, that fraction is WRONG!

It would be

48
-- (9+3)
2

Read it out loud, "Forty-eight divided by 2 times nine plus three!"

48 divided by 2 is 24 times (9 plus 3) which is (12)

24(12) = 288

Any questions?

 

[tre2k4]

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

Not 48÷2(9+3)

 

[wiZe]

Paralogistic reasoning. If you start with the wrong assumption (your method) and use said assumption to check your answer, of course it will work in reverse. lol. That doesn't mean your methodology was correct.

The nice thing about a math problem is you can always check your answer. You can change history over time but never change numbers.

48/2(9+3)= 2 or 48/2(9+3)=288

Use the algebra taught to you as an youngster and the answer is there.

X/2(9+3)= 2 or X/2(9+3)=288

Replace X for any digit and you will get the answer as 2.

 

[Rick Spanish]

Nope, that fraction is WRONG!

It would be

48
-- (9+3)
2

Read it out loud, "Forty-eight divided by 2 times nine plus three!"

48 divided by 2 is 24 times (9 plus 3) which is (12)

24(12) = 288

Any questions?

Any number in front of the Parentheses is multiplies by the sum of the Parentheses. You dont divided 48 by 2. You divide it by the product of the Parenthesis and the number it owns.

 

[cbm_redux]

48÷2(9+3) is asking you to take 48 over 2(9+3) in which you will get 48/24 which equals 2.

No it isn't. 48÷2(9+3) means 48/2 x (9+3) = 288

 

[Jae]

GOTDaaaaaaamn! Seriously my dudes?

When I left for work at 3 this afternoon, this thread was 4 pages.
The fck happened in here?







So.........what's the answer?

 

[nubian]

This problem got brothas and sistas using their brains. It doesn't matter wrong or right but the fact that people are using their brains and thoughts for something other than porn is a positive thing.

which was the sole reason why i made this thread.
i'm loving the deliberation.

 

[tre2k4]

For those that say 2, yall saying Excel, Math.com, Google, TI-8X are all wrong

 

[DarkVoid]

you guys are making a mountain out of mole hill.

1. 9 + 3 = 12


2. 2 x 12 = 24


3. 48 / 12 = 2


The End.

 

[macker007]

2

 

[followup]

Might I add that I was never allowed to use a calculator until I reached precalculus (10th grade) and I had straight As in EVERY math class. Thanks.

 

[Rawness]

For those that say 2, yall saying Excel, Math.com, Google, TI-8X are all wrong

Half these people are just getting a kick out of watching you explain the problem, correctly, from every possible angle.

The other half are your typical BGOL experts. They haven't thought about this problem since learning about it in grade school, yet they still feel the confident in saying that the programmers who were paid to write and debug those programs are all wrong.


(and it may be closer to 20/80 than half & half)

 

[tre2k4]

you guys are making a mountain out of mole hill.

1. 9 + 3 = 12


2. 2 x 12 = 24


3. 48 / 12 = 2


The End.

WRONG


A common technique for remembering the order of operations is the abbreviation "PEMDAS", which is turned into the phrase "Please Excuse My Dear Aunt Sally". It stands for "Parentheses, Exponents, Multiplication and Division, and Addition and Subtraction". This tells you the ranks of the operations: Parentheses outrank exponents, which outrank multiplication and division (but multiplication and division are at the same rank), and these two outrank addition and subtraction (which are together on the bottom rank). When you have a bunch of operations of the same rank, you just operate from left to right. For instance, 15 ÷ 3 × 4 is not 15 ÷ 12, but is rather 5 × 4, because, going from left to right, you get to the division first. If you're not sure of this, test it in your calculator, which has been programmed with the Order of Operations hierarchy. For instance, typesetting this into a graphing calculator, you will get:


calculator screen-shot: 15 / 3 * 4 = 20

Using the above hierarchy, we see that, in the "4 + 2×3" question at the beginning of this article, Choice 2 was the correct answer, because we have to do the multiplication before the addition.

(Note: Speakers of British English often instead use "BODMAS", which stands for "Brackets, Orders, Division and Multiplication, and Addition and Subtraction". Since "brackets" are the same as parentheses and "orders" are the same as exponents, the two acronyms mean the same thing.)
http://www.purplemath.com/modules/orderops.htm

Mnemonics are often used to help students remember the rules, but the rules taught by the use of acronyms can be misleading. In Canada the acronym BEDMAS is common. It stands for Brackets, Exponents, Division, Multiplication, Addition, Subtraction. In other English speaking countries, Brackets may be called Parentheses, or symbols of inclusion and Exponentiation may be called either Indices, Powers or Orders, and since multiplication and division are of equal precedence, M and D are often interchanged, leading to such acronyms as BIMDAS, BODMAS, BOMDAS, BERDMAS, PERDMAS, PEMDAS, and BPODMAS.

These mnemonics may be misleading, especially if the user is not aware that multiplication and division are of equal precedence, as are addition and subtraction. Using any of the above rules in the order "addition first, subtraction afterward" would also give the wrong answer.

10 - 3 + 2 ,
The correct answer is 9, which is best understood by thinking of the problem as the sum of positive ten, negative three, and positive two.

http://en.wikipedia.org/wiki/Order_of_operations

 

[praetor]

Yes I did, dummy.


You have to Simplify. This equation from PurpleMath does the same thing.. The number outside the Parentheses is multiplied by it before you work the problem.

3 is multiplied by the sum of the parentheses, as 2 is in the OP's problem.

You clearly see that the number in front of the Parenthesis (3) is multiplied by the sum of the Parenthesis right?

yes i see that. i'm not disagreeing with the example, i'm saying that because of the way it is structured, it is reinforcing your notion that something outside of the parentheses belongs to it. If in that example, the minus sign to the right of 16 were a division sign, 16 would have to be divided by 3 before multiplying by 25.

 

[half-a-mil]

Might I add that I was never allowed to use a calculator until I reached precalculus (10th grade) and I had straight As in EVERY math class. Thanks.

You, my friend, need to pull that calculator back out b/c the answer is not 2

 

[wiZe]

Might I add that I was never allowed to use a calculator until I reached precalculus (10th grade) and I had straight As in EVERY math class. Thanks.

Some schools are better than others.

 

[followup]

5(10-3) is not the same as 5*10-3....

you have to distribute your 5 across the parentheses...doesn't matter what is in the numerator........I'm here all night to offer tutoring....pretty sure those claiming 288 is the correct answer were not A students in grade school. Just a hunch. Don't be offended

 

[Spectrum]

Might I add that I was never allowed to use a calculator until I reached precalculus (10th grade) Thanks.

 

[tre2k4]

How can something outside the parentheses belong to the parentheses???

 

[Rick Spanish]

For those that say 2, yall saying Excel, Math.com, Google, TI-8X are all wrong

Im saying they are taking the equation a different way. You dont evaluated the operation as is. You have to Simplify.

you guys are making a mountain out of mole hill.

1. 9 + 3 = 12


2. 2 x 12 = 24


3. 48 / 12 = 2


The End.

Pretty much. I guess they didnt teach Simplifying Equations at some of these niggas schools.

 

[followup]

8 pages!! The answer is 2.

You have to work the () first which will give you 12. Then multiply by 2 which gives you 24. 48/24 = 2

Think of it this way. 48/(9+3) = 4.

If you are getting 288 that means you divided 48/2 then multiply by 12 which is not right.

Here is another way to look at it: 48/1 * 1/2 * 1/12

Treat them as fractions.

Here it is theoretical: w=48, x=2, y=9, z=3

w/x(y+z) = w/(xy+xz) = w *(xy+xz)^-1 = w * x^-1 * (y+z)^-1 = 48 * 2^-1 * (9+3)^-1 = 48 * (1/2) * (1/12) = 2

if you are coming up with 288 then you are treating the -1 exponent as a positive; meaning when you inverted the denominator to the numerator you made -1 a positive. This is not right. Example. 1/x = 1*x^-1 which is not equal to 1*x

The answer lies within arithmetic not programming

Master of Applied Math ('09)

sweetie. This is BGOL

 

[Rick Spanish]

yes i see that. i'm not disagreeing with the example, i'm saying that because of the way it is structured, it is reinforcing your notion that something outside of the parentheses belongs to it. If in that example, the minus sign to the right of 16 were a division sign, 16 would have to be divided by 3 before multiplying by 25.

If it was division sign it would be evaluated in the same way.

 

[half-a-mil]

5(10-3) is not the same as 5*10-3....

you have to distribute your 5 across the parentheses...doesn't matter what is in the numerator........I'm here all night to offer tutoring....pretty sure those claiming 288 is the correct answer were not A students in grade school. Just a hunch. Don't be offended

you don't have to distribute in this example. you work inside the parenthesis first, which gives you 7 and then you multiply 5*7=35

 

[Rick Spanish]

How can something outside the parentheses belong to the parentheses???

Its called Simplifying. This is not even a valid equation until you simplify it which is why calculators are taking it literal.

 

[M.H.C.]

No it isn't. 48÷2(9+3) means 48/2 x (9+3) = 288

You may be right but some scientific calcs and online problem solvers that allow variations of the ÷ and the / set up the problem different which gets 2 different answers.



I'm getting rusty with this shit cuz normally I am so sure of my answer but now i'm .


Props Nubian though cuz this has motivated me to really get back on my shit. I don't care if i'm right or wrong.

 

[cbm_redux]

How can something outside the parentheses belong to the parentheses???

It doesn't. They are attempting to solve the problem as if 9 and 3 were unlike terms that cannot be simplified within the grouping symbol. Personally, I blame the public school system.

 

[trick20]

Some schools are better than others.

true....

 

[tre2k4]

5(10-3) is not the same as 5*10-3....

you have to distribute your 5 across the parentheses...doesn't matter what is in the numerator........I'm here all night to offer tutoring....pretty sure those claiming 288 is the correct answer were not A students in grade school. Just a hunch. Don't be offended

You cant do that if theres a division sign in front of it

Only when its by it self like 5(10-3)
or
10-5(10-3)
Multiplication comes before subtracting.

in
10/5(10-3)
Division comes before multiplying and the 5 is under the 10 so you better off multiplying 10(10-3) first and then dividing by 5

So its either
10/5(7)
=2(7)
=14

or
10(7)
-----
5

=
14

 

[followup]

How can something outside the parentheses belong to the parentheses???

Now you are doing the correct thing: asking. any number in front of the parentheses must be distributed across it. Do not collect $200, do not pass go.

2 = 48/2(12) = 48/2(9+3) = 48/(18+6) = 48/24 = 2
you have to solve that equation before any division can occur.

 

[praetor]

5(10-3) is not the same as 5*10-3....

who said that these were equal.

no one who said 288 said that you could have 2*9+3 instead of 2 * (9+3)

 

[tre2k4]

Its called Simplifying. This is not even a valid equation until you simplify it which is why calculators are taking it literal.

but the 2 is attached to the 48÷

 

[M.H.C.]

8 pages!! The answer is 2.

You have to work the () first which will give you 12. Then multiply by 2 which gives you 24. 48/24 = 2

Think of it this way. 48/(9+3) = 4.

If you are getting 288 that means you divided 48/2 then multiply by 12 which is not right.

Here is another way to look at it: 48/1 * 1/2 * 1/12

Treat them as fractions.

Here it is theoretical: w=48, x=2, y=9, z=3

w/x(y+z) = w/(xy+xz) = w *(xy+xz)^-1 = w * x^-1 * (y+z)^-1 = 48 * 2^-1 * (9+3)^-1 = 48 * (1/2) * (1/12) = 2

if you are coming up with 288 then you are treating the -1 exponent as a positive; meaning when you inverted the denominator to the numerator you made -1 a positive. This is not right. Example. 1/x = 1*x^-1 which is not equal to 1*x

The answer lies within arithmetic not programming

Master of Applied Math ('09)

How did it not end here?

Now I am sure of my answer.