This topic is locked
Ahem.
Math Problem
= ?
or 
- matty_batty0
- Member
That would be (ac)/b , why would you look at that and assume the c is underneath the division sign? If anything this proves you wrong, since there are no longer any brackets apparently messing things up, and it agrees with your method perfectly to equal 288.
I think you might have actually just posted the most direct piece of proof so far that it does equal 288
I think you might have actually just posted the most direct piece of proof so far that it does equal 288
This post has been edited by matty_batty0: 11 April 2011 - 03:56 PM
- #103
- 11 April 2011 - 03:49 PM
- Blazer
- Member
Because there is no connection, in mathematical case operation, between a and c that merges them together.
Actually there IS an operation that can merge a and c but that is only when you are out of options for Multiplying, Dividing, Addition and Subtraction.
Which is NOT the case in the given task obviously.
Actually there IS an operation that can merge a and c but that is only when you are out of options for Multiplying, Dividing, Addition and Subtraction.
Which is NOT the case in the given task obviously.
This post has been edited by Blazer: 11 April 2011 - 03:56 PM
- #104
- 11 April 2011 - 03:56 PM
- matty_batty0
- Member
AC/B is the exact same as writing A/B x C though.
If we sub in the values for that equation then we get (48) / (2) x (12) = ? , surely almost every method suggested so far on this thread will find that that equals 288?
If we sub in the values for that equation then we get (48) / (2) x (12) = ? , surely almost every method suggested so far on this thread will find that that equals 288?
This post has been edited by matty_batty0: 11 April 2011 - 04:04 PM
- #105
- 11 April 2011 - 03:59 PM
- JHawkNH
- Member
a/bc is actually shorthand for a/b*c which according to the rules is the same as (a/b)*c or (a*c)/b.
Math is one of my specialties. You may want to check with a math teacher on this one Blaze. They may be better able to explain in person why the answer is 288 and not 2.
Math is one of my specialties. You may want to check with a math teacher on this one Blaze. They may be better able to explain in person why the answer is 288 and not 2.
- #106
- 11 April 2011 - 04:02 PM
- esalaka
- Banned
GUYS
This is a problem of whether or not a(b) should be handled as (ab) in here.
I don't think it should.
I would've added a fancy LaTeX explanation but texlive is taking ages.
a/b*c = a * b^-1 * c = a * c * b^-1 = (ac)/b
∎
This is a problem of whether or not a(b) should be handled as (ab) in here.
I don't think it should.
I would've added a fancy LaTeX explanation but texlive is taking ages.
Blazer, on 11 April 2011 - 03:56 PM, said:
Because there is no connection, in mathematical case operation, between a and c that merges them together.
a/b*c = a * b^-1 * c = a * c * b^-1 = (ac)/b
∎
This post has been edited by esalaka: 11 April 2011 - 04:03 PM
- #107
- 11 April 2011 - 04:05 PM
- Blazer
- Member
No its not, since this indicates that you are missing some knowledge about divisions.
But alright, lets try with one unknown term to get to the right answer.
Example 1, with answer being 288:
48 ÷ x (9 + 3) = 288
48 ÷ 9x + 3x = 288
48 / 12x = 288
4 = 288 x
4 / 288 = x
1 / 72 = x
Example 2, with answer being 2:
48 ÷ x (9 + 3) = 2
48 ÷ 9x + 3x = 2
48 / 12x = 2
4 / x = 2
4 = 2 x
4 / 2 = x
2 = x
This indicates that 288 is wrong, and that 2 is correct answer to this task.
And esalaka, please read my whole post and you'll notice that I DID also mention that there is an operation which is used only in CERTAIN cases as stated.
But alright, lets try with one unknown term to get to the right answer.
Example 1, with answer being 288:
48 ÷ x (9 + 3) = 288
48 ÷ 9x + 3x = 288
48 / 12x = 288
4 = 288 x
4 / 288 = x
1 / 72 = x
Example 2, with answer being 2:
48 ÷ x (9 + 3) = 2
48 ÷ 9x + 3x = 2
48 / 12x = 2
4 / x = 2
4 = 2 x
4 / 2 = x
2 = x
This indicates that 288 is wrong, and that 2 is correct answer to this task.
And esalaka, please read my whole post and you'll notice that I DID also mention that there is an operation which is used only in CERTAIN cases as stated.
This post has been edited by Blazer: 12 April 2011 - 01:19 AM
- #108
- 11 April 2011 - 04:06 PM
- matty_batty0
- Member
No no no, no matter how many unknowns you add, if you have the order wrong it will still be wrong. Please just answer this one, show how it could possibly equal 2.
Quote
(48) / (2) x (12) = ?
This post has been edited by matty_batty0: 11 April 2011 - 04:10 PM
- #110
- 11 April 2011 - 04:09 PM
- matty_batty0
- Member
because this is the exact equation you posted above, it just has the numbers for a, b and c subbed in.
If you want just consider it to be this-
48 / 2 x 12 = ?
I just added brackets to make it easier to read
Quote
a /b c = ?
If you want just consider it to be this-
48 / 2 x 12 = ?
I just added brackets to make it easier to read
This post has been edited by matty_batty0: 11 April 2011 - 04:15 PM
- #112
- 11 April 2011 - 04:13 PM
- JHawkNH
- Member
You had alreay screwwed up example one at this point..
48 ÷ x (9 + 3) = 288
48 ÷ 9x + 3x = 288
You forgot to stick with the order of operations, left to right.
the equation can be rewritten 48 ÷ x * (9 + 3).
Because * and ÷ are at the same level you have to go from left to right.
That means that you have to do the 48 ÷ x before the multiplication to (9 + 3).
48 ÷ x (9 + 3) = 288
48 ÷ 9x + 3x = 288
You forgot to stick with the order of operations, left to right.
the equation can be rewritten 48 ÷ x * (9 + 3).
Because * and ÷ are at the same level you have to go from left to right.
That means that you have to do the 48 ÷ x before the multiplication to (9 + 3).
- #114
- 11 April 2011 - 04:15 PM
- esalaka
- Banned
JHawkNH, on 11 April 2011 - 04:15 PM, said:
You had alreay screwwed up example one at this point..
48 ÷ x (9 + 3) = 288
48 ÷ 9x + 3x = 288
You forgot to stick with the order of operations, left to right.
the equation can be rewritten 48 ÷ x * (9 + 3).
Because * and ÷ are at the same level you have to go from left to right.
That means that you have to do the 48 ÷ x before the multiplication to (9 + 3).
48 ÷ x (9 + 3) = 288
48 ÷ 9x + 3x = 288
You forgot to stick with the order of operations, left to right.
the equation can be rewritten 48 ÷ x * (9 + 3).
Because * and ÷ are at the same level you have to go from left to right.
That means that you have to do the 48 ÷ x before the multiplication to (9 + 3).
This is what everyone has been trying to say.
Then Blazer comes with his NO U and pastes that faulty explanation again. I mean, I dunno why I even try any more. I'm just trying to provoke him to make him see he's wrong, derp.
- #115
- 11 April 2011 - 04:18 PM
- matty_batty0
- Member
aww, chin up Esalaka, no reason to loose sleep over it 
- #116
- 11 April 2011 - 04:20 PM
- Blazer
- Member
esalaka, on 11 April 2011 - 04:18 PM, said:
JHawkNH, on 11 April 2011 - 04:15 PM, said:
You had alreay screwwed up example one at this point..48 ÷ x (9 + 3) = 28848 ÷ 9x + 3x = 288You forgot to stick with the order of operations, left to right.the equation can be rewritten 48 ÷ x * (9 + 3).Because * and ÷ are at the same level you have to go from left to right.That means that you have to do the 48 ÷ x before the multiplication to (9 + 3).
The problem is the bracket there which indicates that it needs to be removed.
48 / 2 x (9+3)
48 / 2 x (12) - note the bracket is not removed and that it still needs to be solved
48 / 24 - bracket is removed
Result ending up in: 2
288 would be correct only if the bracket in the task is not even there from the start
- #117
- 11 April 2011 - 04:28 PM
- matty_batty0
- Member
There is not the slightest part in any area of any maths which would say 20 does not equal (20), they are the exact same thing in every way.
This post has been edited by matty_batty0: 11 April 2011 - 04:31 PM
- #118
- 11 April 2011 - 04:30 PM
- Craft aids
- That doesn't sound like a rape. That sounds like suprise sex
Banned 
explanation one
48 ÷ x (9 + 3) = 2
48 ÷ 9x + 3x = 2
48 / 12x = 2
4 / x = 2
4 = 2 x
4 / 2 = x
2 = x
explanation two.
48 ÷ x (9 + 3) = 288
((48*9)+(48*3)) ÷ x = 288
(576) = 288x
2 = x
This is not an issue off which version of math works correctly. If you hold yourself to the conventions of the math you use and if the problem was built under the same conventions, you will get a legitamate answer.
This is not an issue of correct and incorect answers.
This is purely and issue of comunication which is the field of the broken grammer that was exploited here.
Blazer, brackets only give priority to the contense.
48 ÷ x (9 + 3) = 2
48 ÷ 9x + 3x = 2
48 / 12x = 2
4 / x = 2
4 = 2 x
4 / 2 = x
2 = x
explanation two.
48 ÷ x (9 + 3) = 288
((48*9)+(48*3)) ÷ x = 288
(576) = 288x
2 = x
This is not an issue off which version of math works correctly. If you hold yourself to the conventions of the math you use and if the problem was built under the same conventions, you will get a legitamate answer.
This is not an issue of correct and incorect answers.
This is purely and issue of comunication which is the field of the broken grammer that was exploited here.
Blazer, brackets only give priority to the contense.
- #119
- 11 April 2011 - 04:38 PM
- esalaka
- Banned
Blazer, on 11 April 2011 - 04:28 PM, said:
48 / 2 x (12) - note the bracket is not removed and that it still needs to be solved
I have never heard anything this stupid in my life. (in the area of mathematics, mind you)
Craft aids has a point but as far as I know it's universally accepted that ab isn't handled specially. Eg. it's just shorthand for a * b which then expands this to (48/2)9 + (48/2)3 = 24 * 9 + 24 * 3 = 216 + 72 = 288
Every single calculator I know of (Including bc(1) and Wolfram|Alpha) follows the order of operations like this. Coincidence? I think not.
This post has been edited by esalaka: 11 April 2011 - 04:48 PM
- #120
- 11 April 2011 - 04:43 PM
- Craft aids
- That doesn't sound like a rape. That sounds like suprise sex
Banned
Math issues? CALCULATOR TO THE RESCUE! Like those things weren't retarded anyway.
Brackets are done first.
I demand we see the problam with the simple addition already solved from this point on.
48/2*12
Can we do that?
Then we can be arguing over simple
(48/2)*12
and
48/(2*12)
because the distributive property is un needed clutter.
Brackets are done first.
I demand we see the problam with the simple addition already solved from this point on.
48/2*12
Can we do that?
Then we can be arguing over simple
(48/2)*12
and
48/(2*12)
because the distributive property is un needed clutter.
This post has been edited by Craft aids: 11 April 2011 - 04:59 PM
- #121
- 11 April 2011 - 04:59 PM
- esalaka
- Banned
Kaxbe, on 11 April 2011 - 05:00 PM, said:
Hey, let's all call each other idiots. That seems like a good idea.
Yeah, I thought so, too.
Also, Craft aids, sorry I was not reducing 9+3 I have no idea why.
It still is the same calculation, as you very well know :>
- #123
- 11 April 2011 - 05:01 PM
- Kaxbe
- Member
esalaka, on 11 April 2011 - 04:43 PM, said:
Blazer, on 11 April 2011 - 04:28 PM, said:
48 / 2 x (12) - note the bracket is not removed and that it still needs to be solved
I have never heard anything this stupid in my life. (in the area of mathematics, mind you)
Craft aids has a point but as far as I know it's universally accepted that ab isn't handled specially. Eg. it's just shorthand for a * b which then expands this to (48/2)9 + (48/2)3 = 24 * 9 + 24 * 3 = 216 + 72 = 288
Every single calculator I know of (Including bc(1) and Wolfram|Alpha) follows the order of operations like this. Coincidence? I think not.
- #124
- 11 April 2011 - 05:02 PM
- matty_batty0
- Member
I can see nations going to war over this argument 
...but then again, they probably have before for less.
...but then again, they probably have before for less.
This post has been edited by matty_batty0: 11 April 2011 - 05:05 PM
- #125
- 11 April 2011 - 05:04 PM
- Craft aids
- That doesn't sound like a rape. That sounds like suprise sex
Banned
Craft aids, on 11 April 2011 - 04:59 PM, said:
Math issues? CALCULATOR TO THE RESCUE! Like those things weren't retarded anyway.
SEE?
IT'S A DANM AGREEMENT ISSUE.
AT THIS TIME THE GRAMMER FOR MATH IS BROKEN AND ALL MATH WILL BE INVALID UNTIL WE CAN AGREE ON JUST WHAT MATH IS.
Be glad that it will still be effective for the user, just no one will be able to read it.
- #126
- 11 April 2011 - 05:07 PM
- Craft aids
- That doesn't sound like a rape. That sounds like suprise sex
Banned
Wow, you like math quite a bit don't you?
Next time, grow a dependancy on paper instead.
Next time, grow a dependancy on paper instead.
- #128
- 11 April 2011 - 05:10 PM
- Craft aids
- That doesn't sound like a rape. That sounds like suprise sex
Banned
My post was ment to be taken literal and to have all the extra ideas that you could come up with by reading it ignored. How did you miss the dry?
Even dryer and not even potent humor ignored, I agree that math is useful and I actualy meant what I said about paper. Then your reality can't be turned on it's ear when you find out that devices have flaws.
Even dryer and not even potent humor ignored, I agree that math is useful and I actualy meant what I said about paper. Then your reality can't be turned on it's ear when you find out that devices have flaws.
- #131
- 11 April 2011 - 05:20 PM
- esalaka
- Banned
Craft aids, on 11 April 2011 - 05:20 PM, said:
My post was ment to be taken literal and to have all the extra ideas that you could come up with by reading it ignored. How did you miss the dry?
Even dryer and not even potent humor ignored, I agree that math is useful and I actualy meant what I said about paper. Then your reality can't be turned on it's ear when you find out that devices have flaws.
Even dryer and not even potent humor ignored, I agree that math is useful and I actualy meant what I said about paper. Then your reality can't be turned on it's ear when you find out that devices have flaws.
I was sort of expecting a calculator that did it differently but was surprised by TI's inconsistency with handling something like this. Although it could be that old calculators did one way and new the other, I dunno.
- #132
- 11 April 2011 - 05:32 PM
- Craft aids
- That doesn't sound like a rape. That sounds like suprise sex
Banned
Why don't we just require "()" for every operation? It would save us some issue if that was the grammer. Then agian, you would have to know what to put them over.
There have been an equle number of arguments as to why someone would devide first. The cornerstone being that it is leftmost.
DFA, on 11 April 2011 - 05:35 PM, said:
im 100% sure its 2, and there have been enough reasons in this thread for it being that way 
There have been an equle number of arguments as to why someone would devide first. The cornerstone being that it is leftmost.
- #134
- 11 April 2011 - 05:38 PM
- Craft aids
- That doesn't sound like a rape. That sounds like suprise sex
Banned
And to you, her math teacher probably taught her that multiplication is always before devision.
I have said this so much, the issue is with agreeance and we don't have any.
I have said this so much, the issue is with agreeance and we don't have any.
- #136
- 11 April 2011 - 05:42 PM
- esalaka
- Banned
Craft aids, on 11 April 2011 - 05:38 PM, said:
Why don't we just require "()" for every operation? It would save us some issue if that was the grammer. Then agian, you would have to know what to put them over.
We pretty much do. And it's not like this sort of a problem would arise often in reality, so it doesn't really matter, either.
- #137
- 11 April 2011 - 05:45 PM
- Craft aids
- That doesn't sound like a rape. That sounds like suprise sex
Banned
Effectively, this does not invalidate the usage of math by an indevidual.
It invalidates the comunication of math from one person to anouther.
Either way, it is solved by just not making a problem like that one.
On that note, people are not that responcable.
It invalidates the comunication of math from one person to anouther.
Either way, it is solved by just not making a problem like that one.
On that note, people are not that responcable.
- #138
- 11 April 2011 - 05:47 PM
- Craft aids
- That doesn't sound like a rape. That sounds like suprise sex
Banned
Blazer, on 11 April 2011 - 06:21 PM, said:
Quote
I'm not repeating myself this time.
Go read.
- #140
- 11 April 2011 - 06:25 PM
- Blazer
- Member
Craft aids, that's only my response for the picture
If you read what I wrote previously you'll notice I actually did some calculating on the paper and just re-typed it on the computer to post it...
If you read what I wrote previously you'll notice I actually did some calculating on the paper and just re-typed it on the computer to post it...
This post has been edited by Blazer: 11 April 2011 - 06:45 PM
- #141
- 11 April 2011 - 06:30 PM
- Craft aids
- That doesn't sound like a rape. That sounds like suprise sex
Banned
And you used one of the two syntaxes to do it. That does not make that syntax more correct then the other one.
- #142
- 11 April 2011 - 06:34 PM
- Craft aids
- That doesn't sound like a rape. That sounds like suprise sex
Banned
I showed both a few times now.
One moment, I will go quote myself.
The issue pivots around either multiplying first or ddoing the rightmost problem(deviding) first.
One moment, I will go quote myself.
Craft aids, on 10 April 2011 - 04:49 AM, said:
48÷2(9+3)
Without a doubt, the parenthesis make the first move clear.
48÷2*12
At this point, one must choose between the order of operations that goes based on symbols only,( () then * then ÷ then + then - ) and the system that goes based on groupings with a secondary system of right to left( () then * and ÷ then + and -). In the first system we always multiply before we divide and in the second system we chose the right most of multipliers and dividers.
48÷24 or 24*12
2 or 288
The issue is, I have heard of it being done both ways it it would be immposable to test because anything created to test either one would always be correct in the one it was made for and incorrect in the other.
Without a doubt, the parenthesis make the first move clear.
48÷2*12
At this point, one must choose between the order of operations that goes based on symbols only,( () then * then ÷ then + then - ) and the system that goes based on groupings with a secondary system of right to left( () then * and ÷ then + and -). In the first system we always multiply before we divide and in the second system we chose the right most of multipliers and dividers.
48÷24 or 24*12
2 or 288
The issue is, I have heard of it being done both ways it it would be immposable to test because anything created to test either one would always be correct in the one it was made for and incorrect in the other.
The issue pivots around either multiplying first or ddoing the rightmost problem(deviding) first.
- #144
- 11 April 2011 - 06:57 PM
- Blazer
- Member
I've seen that and allow me to quote myself and check the first sentence...
Quote
I re-typed the one that made most sense to me, filled three papers trying to calculate that in both ways and I still do not see any way how that task ends up correctly with 288 as result..
- #145
- 11 April 2011 - 07:04 PM
- Craft aids
- That doesn't sound like a rape. That sounds like suprise sex
Banned
48÷2*12
One way that is taught is that multiplication and devision have the same prioraty and are chosen from left to right.
So you would do the problem like this in that system.
(48÷2)*12
24*12
288
And that's how you could end up at that answer.
One way that is taught is that multiplication and devision have the same prioraty and are chosen from left to right.
So you would do the problem like this in that system.
(48÷2)*12
24*12
288
And that's how you could end up at that answer.
- #146
- 11 April 2011 - 07:07 PM
- Blazer
- Member
As I recall we were thought that multiplying has priority over dividing, so ...
...makes almost no sense at all
Quote
48÷2*12
One way that is taught is that multiplication and devision have the same prioraty and are chosen from left to right.
So you would do the problem like this in that system.
(48÷2)*12
24*12
288
One way that is taught is that multiplication and devision have the same prioraty and are chosen from left to right.
So you would do the problem like this in that system.
(48÷2)*12
24*12
288
...makes almost no sense at all
This post has been edited by Blazer: 11 April 2011 - 07:20 PM
- #147
- 11 April 2011 - 07:18 PM
- JHawkNH
- Member
Blazer, on 11 April 2011 - 07:18 PM, said:
As I recall we were thought that multiplying has priority over dividing, so ...
Then you were taught wrong. Neither multiplying or dividing has priority over the other. That is why they must be worked from left to right.
- #148
- 11 April 2011 - 07:58 PM
JHawkNH is correct. Multiplication does not have priority over division (since division is just multiplication by the reciprocal). And when two operators have the same level of precedence, they are evaluated in order from left to right.
Now, consider the original equation once again:
Some people attempt to use the distributive property to simplify the equation, as follows:
However, this is wrong, because then you're multiplying before dividing. Hence, you're doing the operations out of order.
This is why the correct answer is 288 and not 2.
Now, consider the original equation once again:
48÷2(9+3) = ?
Some people attempt to use the distributive property to simplify the equation, as follows:
48÷(18 + 6) = ?
However, this is wrong, because then you're multiplying before dividing. Hence, you're doing the operations out of order.
This is why the correct answer is 288 and not 2.
- #149
- 11 April 2011 - 09:15 PM
Kaxbe, those pictures are amazing.
As I mentioned on pg 2, this problem is the confusion of terms with the lack of brackets.
Calculators won't do anything you didn't tell them so why are re relying on them?
Unfortunately, this being a low level arithmetic problem, the writers did not flush it out as much as they could have.
I blame writing!
If 48/2(3+9) does equal 288, why didn't the writes use any other function to multiply the Term_1=[ 48/2 ] with Term_2=[ (3+9) ]
The writers could have written Term_1 x Term_2 Or Term_1 * Term_2
But they didn't and everyone whom supports 288 has to input the "*" or "x" to do their arithmetic.
In any case, if they intend to have (3+9) being multiplied by 48, why didn't they just have it next to 48?
Instead they use "2(3+9)"
This phrasing is usually associated with factoring. It could be just (6+18) with a factored out 2.
In which case, the answer is 2.
So it comes to if 48/2(3+9) is [(48)/(2(3+9)] or [(48(3+9))/(2)]. Just as Blazer asked on the top of page 3.
Warning: I say everything with a bias of a physicist. It is very important for us to know where terms are within an equation so there is always an abundance of brackets. And another change would be that my equations and math are written in the simplest way possible, and not meant to test your arithmetic knowledge. Give me Algebra, Geometry, Calculus I, II, III, Differential Equations, but just not Stats and I'll give you a more confidence answer than this. Now, I'll stop beating this horse... but this forum has already killed it.
As I mentioned on pg 2, this problem is the confusion of terms with the lack of brackets.
Calculators won't do anything you didn't tell them so why are re relying on them?
Unfortunately, this being a low level arithmetic problem, the writers did not flush it out as much as they could have.
I blame writing!
If 48/2(3+9) does equal 288, why didn't the writes use any other function to multiply the Term_1=[ 48/2 ] with Term_2=[ (3+9) ]
The writers could have written Term_1 x Term_2 Or Term_1 * Term_2
But they didn't and everyone whom supports 288 has to input the "*" or "x" to do their arithmetic.
In any case, if they intend to have (3+9) being multiplied by 48, why didn't they just have it next to 48?
Instead they use "2(3+9)"
This phrasing is usually associated with factoring. It could be just (6+18) with a factored out 2.
In which case, the answer is 2.
So it comes to if 48/2(3+9) is [(48)/(2(3+9)] or [(48(3+9))/(2)]. Just as Blazer asked on the top of page 3.
Warning: I say everything with a bias of a physicist. It is very important for us to know where terms are within an equation so there is always an abundance of brackets. And another change would be that my equations and math are written in the simplest way possible, and not meant to test your arithmetic knowledge. Give me Algebra, Geometry, Calculus I, II, III, Differential Equations, but just not Stats and I'll give you a more confidence answer than this. Now, I'll stop beating this horse... but this forum has already killed it.
This post has been edited by Vanvoltra: 11 April 2011 - 09:23 PM
- #150
- 11 April 2011 - 09:21 PM