Math Hurts: 48÷2(9+3)

[Danoff]

That's why you don't write it like that.

This ^^

No point in discussing poor notation.

 

[grymey]

Then you shorten it to 48 over 2(9+3) as the denominator.



Basically turning the division into the corresponding multiplication, I think

But then you wouldn't be doing the "implied" multiplication of the brackets first, which kills the argument for everybody saying 2.

 

[grymey]

That's because you've made it into a different yet similar equation. Instead of 48 divided by 2 multiplied by (9+3), you've changed it to 48 multiplied by 0.5 multiplied by (9+3). There is no division in your equation.

48÷2 is the same thing as 48*1/2.

 

[ranhammerR34]

It is.... crap... it has to be if following the right way of doing math problems, two (2), right guys? No, wait it is 288! Just noticed it. --- Randy

 

[niky]

Question is... is it

0.5 * (9+3)

or

0.5 ÷ (9+3)?

 

[Azuremen]

Question is... is it

0.5 * (9+3)

or

0.5 ÷ (9+3)? ​

​

 

[nk4e]

GTP complicating a math problem, one rule at a time.

 

[Omnis]

Well, the answer is 2. Please answer 288 though so that I may be statistically ahead of the class.

Also, this:

 

[grymey]

Oh no, 48*1/(2(9+3)) = 2. I'm confused now.

48÷2(9+3) could be (48/2)(9+3)= 288
or it could be 48/(2(9+3))= 2
48÷2(9+3) could be 48*1/2(9+3)
which could be ((48*1)/2) (9 + 3) = 288
or 48*1/(2(9+3))= 2

You could probably write it out a bunch of other ways and get either 2 or 288. I'm done with this troll thread.

 

[1251Division]

This math problem is a great question to get everyone to really think about 1) math, and 2) the importance of communicating clearly. In practical math (i.e. the real world), a majority of numbers have units assigned to them, because they represent some physical dimension. These units can often help clarify a problem like that given in the OP.

Let's say it takes 48-hours for 1-person to collect 9-brown eggs and 3-white eggs. 2-people are doing this work. The question is: How many eggs per hour were collected on average?

Answer:____________ ???


Without even needing symbols, you can use your brain to figure out the answer...

===
Ok, here's a new one:

(49)^(1/2)
480/[2(9+3)]
SQRT(3^2+4^2)

Hint--first two are letters

 

[Legendary]

The division bar is a grouping tool. 48 is one group and 2(9+3) is another. So the problem should look like (48)/(2(9+3)) = 2.

This exactly, this is how I have been taught.

If anything can be simplified on either the top, bottom or both it should be done so before moving onto the next phase of the question.
Firstly the brackets are to be done, brackets always come first. Therefore the question turns into:

48/ 2(12)
The '2(12)' is '2*12' which is 24.
Therefore:
48/ 24
And 48 divided by 24 is, everybody? 2.

 

[uMadson?]

I'll also explain my stand. PEMDAS is PEMDAS. And divide/multiply/add/subtract from left to right.

So...
48/2(9+3)
=48/2(12) - parentheses first
=24(12) - divide from left to right
=288 - multiply

 

[GTR3mh]

48÷2 is the same thing as 48*1/2.

Wrong. Division is math is written as a fraction in proper formatting. Simply multiplying it will give you the 288 answer every time.

 

[Blitz187]

I hate math.... But I got 288...

 

[lbsf1]

Bodmas is all very well and good, however you then end up with 48 / 2,12 . There is no operation between the 2 and 12. If it was algebra then its timesing them by each other, however in this case its just 1 number after another.

If I was to pretend it was algebra then its
BODMAS, brackets first. 9+3 = 12
This is where the problem is now you can either times the 12 by 2 and divide that (which is wrong due to bodmas), or do what I'm going to do now.
Divide 48/2 (I don't have a divide button on my keyboard). Now you have 24 * 12. Which is 288.

 

[Omnis]

Bodmas is all very well and good, however you then end up with 48 / 2,12 . There is no operation between the 2 and 12. If it was algebra then its timesing them by each other, however in this case its just 1 number after another.

Dude. Seriously... I think I should close this before we get any dumber.

 

[Blitz187]

Dude. Seriously... I think I should close this before we get any dumber.

So I is dumb, I got 288? Never been good at math though.... Can we get some biology or chemistry questions??

 

[DGiant2000]

Ok, as a Maths teacher I feel I should weigh in here. Firstly, you'd be an idiot to write a calculation like that (other than to ask an interesting question and confuse people!) as it is completely ambiguous. The divide sign is rarely used above GCSE level (high school I believe) and should be written in fractional form, it depends on whether just the 2 is the denominator or the 2 and the brackets. I would interperet th answer as 2 as I would expand and simplify the brackets first, then do the division, although there are arguments to the contrary as stated above.

One thing I would not rely on is BODMAS/BIDMAS/BEDMAS (never seen and e in it, I guess its for exponential), as it can often be incorrect - also multiplication/division and addition/subratction have equal footing in the order stakes, you should simply perform them left to right.

The other thing I would definitely not rely on is a calculator as, due to the constraints of their programming, they often get things wrong as well. Case in point, type in -2 sqaured and you will get the answer -4 and not 4. Why? because rather than recognising a negative number, the calculator does the power first (squares the 2) then accounts for the negative next, ala BODMAS.

In summary, never write that sum, use brackets more wisely to indicate order and don't use a divide sign

 

[Omnis]

So I is dumb, I got 288? Never been good at math though.... Can we get some biology or chemistry questions??

No, you aren't, but spending all this time justifying the wrong answer is. The best we can say is that it's ambiguous until you re-write it correctly. And when you do, it's 2.

edit: As a special bonus, this thread made me go look up the actual name for the vinculum (the fraction line thingy) and the other symbols for division. I did this because I remember them from a question in a quizbowl tournament. The line with a dot above and below is called an obelus. As I said before, the vinculum also serves as a grouping notation. There is of course the slash, and then finally there is the solidus which is a slash/vinculum typographical hybrid. It occured to me just now that Solidus Snake from MGS gets his name for this fraction bar and not because "He's kinda like Solid Snake, but with some Liquid. Liquidy-Solid must make Solid-ous." Makes perfect sense now considering the story.

 

[1251Division]

No, you aren't, but spending all this time justifying the wrong answer is. The best we can say is that it's ambiguous until you re-write it correctly. And when you do, it's 2.

^^^ For the WIN

 

[Daniel]

What Omnis said. If it's 48/2(9+3), then it's 2. But if it's , then it's 288. The fraction line thingy groups it, the division line doesn't.
So it depends on the sign. And in this thread title's case [48÷2(9+3)], it's 288.

 

[Famine]

That's why you don't write it like that.

This ^^

No point in discussing poor notation.

The order of multiplication and division doesn't matter, you simply do them from left to right. The issue here is that ya'll are misunderstanding what division is. It's akin to a grouping symbol, and that's why 288 is wrong. In my previous post I showed every step to doing this problem, which involves grouping the 48 as the numerator and 2(9+3) as the denominator, FOILing the parenthesis, then performing the division.

This problem is so basic I've been arguing with a friend over it for a half hour because I didn't know why division was a grouping symbol.

These.

Written out correctly, the problem is:

___48___
2 x (9+3)​

Now tell me that is "288"...

Anybody? Anybody? Bueller?

 

[Omnis]

What Omnis said. If it's 48/2(9+3), then it's 2. But if it's , then it's 288. The fraction line thingy groups it, the division line doesn't.
So it depends on the sign. And in this thread title's case [48÷2(9+3)], it's 288.

Division DOES group it no matter what sign you use! God! That's why division comes before multiplication on the Police-Ecdysis-Daddy-Mommy-Auntie-Subaru order of operations mnemonic thing.

 

[Blitz187]

No, you aren't, but spending all this time justifying the wrong answer is. The best we can say is that it's ambiguous until you re-write it correctly. And when you do, it's 2.

So now if I understand correctly the way its written in the first post it could be either values? Or it's just moot all together? The division sign is what threw everything off course for some then, including me. Once again, I hate math...

 

[JediRage]

Its 288.

You forgot to put brackets here (2(9+3)).

EDIT:

Oh I forgot, you have to open the brackets first, (9+3) then multiply it with 2 and then the division comes into play. Work your way from the brackets.

BODMAS
Bracket Open Division Multiplication Addition Subtraction

 

[lukecfc]

Come on guys. Anyone who has done 4th or 5th form maths is not going to leave that bracket alone while they divide the 48 by 2 right?

 

[Stevisiov]

I went for the BODMAS answer in the poll, but truthfully I would normally work with the implied version in engineering. If you write it as a fraction, its much more clear that the answer should be 2.

You can easily get two answers here depending on which interpretation you use. Not ideal.

For all intents and purposes, the answer is 2.

 

[Dragonistic]

You could also set the problem = to X, though it may look much more complicated then it needs it helps to show how the 2(9+3) should be treated.

48÷2(9+3) = X
(48÷2(9+3))*(2(9+3))=(2(9+3))*X (I'd usually skip this step and go straight to the next line but for illustrative purposes it's here)

- Note: However you look at it the first half of the left side, the 2(9+3)'s will now cancel each other as you're multiplying by the same thing you're dividing by regardless which way around you do it as you're multiplying the entire left side by 2(9+3) or 24 there's no reason to treat the division differently as if it were divide by 2 and then multiply by 12 (until you do what I'll discuss at the end of the post, which you shouldn't do).

48 = 2(9+3)*X
48 = 2(12)*X
48 = 24X
48/24 = 2 = X

At higher levels of education you would be expected to assume, as stated by others, that the 2(9+3) is it's own item and would be the denominator of the 'fraction'. However, again as stated if you were to write the multiplication symbol as 2*(9+3) it changes the question as silly as it sounds. My graphical calculator agrees as I have both on screen now with 2 different answers, but we're being asked the former so there is only one answer. We've had a similar problem at university and this is the expected way to do it, not neccessarily set to X but assume 2(9+3) as a denominator or (2(9+3)), in the UK at least.

Edit: Just presenting it how you're often asked to do this type of question at higher levels, they love to ask you to solve for X rather then just give you some numbers to crunch to try to make you begin to learn how to interpret algebraic equations and the principles you'll follow for later much more complicated questions.

 

[Joel]

Is it okay if I change my answer to this:

I can't even see what number that is

 

[Keef]

___48___
2 x (9+3)​

I see what you did there. I can do math but I can't figure out how to type it!

EDIT: Also, I used the wrong term in my other post. You don't FOIL the parenthesis because there is only one term. It's called distributing the 2, which is another word I haven't used in so long I forgot what it was.