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### Author Topic: A math problem.  (Read 10096 times)

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#### MariaE

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##### Re: A math problem.
« Reply #30 on: November 02, 2012, 02:01:23 AM »
Squeakers, in that example the operations are all equal. That makes a difference.

The answer to the problem as written is 7.

Dane by birth, Kiwi by choice

#### Iris

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##### Re: A math problem.
« Reply #31 on: November 02, 2012, 02:03:09 AM »
^Aeris beat me to that one.

Without any brackets and as presented the answer is 7.

If formatted as MrsJWine's second example it would be 4. This is one of the difficulties with the use of / for division. If you are presenting the equation linearly and want it to be as in the second example you must use brackets.
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#### Steve

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##### Re: A math problem.
« Reply #32 on: November 02, 2012, 02:53:01 AM »
Add me to the '7' - camp

#### DaisyG

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##### Re: A math problem.
« Reply #33 on: November 02, 2012, 06:51:17 AM »
I also vote for 7 and hope the update with the radio station's answer gets posted soon!

I was taught the order of operations as BODMAS - Brackets (parentheses), of (exponents), division, multiplication, addition, subtraction.

#### PastryGoddess

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##### Re: A math problem.
« Reply #34 on: November 02, 2012, 06:53:04 AM »
PastryGoddess, you have an oops, I think.  In 6 - 0 + 1, you can't reduce that to 6 - 1, it would be 6 + 1.  The - is attached to the 0 (it's the same as saying 6 + -0 + 1.  So you would get 7 instead of 5.

since when can 0 be negative?  Please explain or link to a page explaining.  Since addition comes before subtraction I added 1 to 0 then subtracted 6 from there.

http://www.math.com/school/subject1/lessons/S1U1L10DP.html
« Last Edit: November 02, 2012, 06:57:47 AM by PastryGoddess »

#### MariaE

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##### Re: A math problem.
« Reply #35 on: November 02, 2012, 07:07:25 AM »
PastryGoddess, you have an oops, I think.  In 6 - 0 + 1, you can't reduce that to 6 - 1, it would be 6 + 1.  The - is attached to the 0 (it's the same as saying 6 + -0 + 1.  So you would get 7 instead of 5.

since when can 0 be negative?  Please explain or link to a page explaining.  Since addition comes before subtraction I added 1 to 0 then subtracted 6 from there.

http://www.math.com/school/subject1/lessons/S1U1L10DP.html

MommyPenguin has it right. I know it doesn't make sense to talk about 'negative zero', but the logic would be the same no matter the number:
6 - x + 3 = 6 + (-x) + 3

Subtraction and addition are equal in the order of operations (precisely because subtraction can be rewritten as adding a negative number), so should be calculated left-to-right. Funnily enough this also means that 6 - x + 3 = 6 + 3 - x = 3 + 6 - x = ...

Dane by birth, Kiwi by choice

#### Iris

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##### Re: A math problem.
« Reply #36 on: November 02, 2012, 07:58:16 AM »
PastryGoddess, you have an oops, I think.  In 6 - 0 + 1, you can't reduce that to 6 - 1, it would be 6 + 1.  The - is attached to the 0 (it's the same as saying 6 + -0 + 1.  So you would get 7 instead of 5.

since when can 0 be negative?  Please explain or link to a page explaining.  Since addition comes before subtraction I added 1 to 0 then subtracted 6 from there.

http://www.math.com/school/subject1/lessons/S1U1L10DP.html

0 doesn't need to be negative to follow this. "6-0+1" is just "take nothing away from 6 and then add 1".  Zero operates the same way as any other number.
"Can't do anything with children, can you?" the woman said.

Poirot thought you could, but forebore to say so.

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##### Re: A math problem.
« Reply #37 on: November 02, 2012, 08:38:05 AM »
1

#### WillyNilly

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##### Re: A math problem.
« Reply #38 on: November 02, 2012, 10:05:42 AM »
I (and DH) learned absolutely unquestionably without parenthesis ones does math in order left to right.  So as written the answer is 1.

If written 6 - (1X0) + (2/2) it would be 7.

You're telling me neither you nor your DH learned the order of operations? That's very odd.

http://www.math.com/school/subject2/lessons/S2U1L2DP.html

You just linked a page explaining order of operations. WillyNilly is saying that she and her DH learned to do the whole thing from left to right, instead of doing multiplication/division left to right first, then addition/subtraction left to right afterwards. Which means WillyNilly is saying that neither she nor her DH were taught the order of operations. Which I find odd.

Odd as it may be, that's what I was taught, and that's what DH was taught.  That's why parenthesis are used (or at least it was always my understanding) - to show you in this case its not left to right, in this example you do these bits first.  Otherwise why ever bother with using parenthesis?  If its always multiplication first the parenthesis are extraneous.

And it should be noted both DH and I went to high school in different states (me NY him CT) so this was across curriculums.

And this all really explains why people hate math with such burning passions.  Its not clear or intuitive, or taught in universally similar ways.  In fact I just asked my dad, a (now retired, and admittedly not math) teacher for over 35 years and he said "left to right if no parenthesis".

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##### Re: A math problem.
« Reply #39 on: November 02, 2012, 10:26:53 AM »
Parenthesis are basically for when you don't want to follow the order of operations.

Like if you want 6x(2+4) cause that would be 36 versus 6x2+4 which would be 16.

#### MOM21SON

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##### Re: A math problem.
« Reply #40 on: November 02, 2012, 10:30:46 AM »
well, overnight brought a few more 6's , 7's and 5's.  Tons of ones and the newest trend is 3.5.

The station will not be posting the answer until 6:30 om tonight EST.  I certainly will post it here.

There are almost 5,000 responses on the page.  And just incase he is right, DS was the first person to say 6.

#### MariaE

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##### Re: A math problem.
« Reply #41 on: November 02, 2012, 11:16:00 AM »
Parenthesis are basically for when you don't want to follow the order of operations.

Or if you don't want to follow left-to-right in the case of equal operations.

I.e. 10-5-2 = 3 whereas 10-(5-2) = 7

MOM21SON, if the station reveals the answer to be anything other than 7, they are wrong. I blame the increased use of calculators, because they don't care one whit about order of operations and take everything left-to-right.

Dane by birth, Kiwi by choice

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##### Re: A math problem.
« Reply #42 on: November 02, 2012, 11:20:27 AM »
well, overnight brought a few more 6's , 7's and 5's.  Tons of ones and the newest trend is 3.5.

The station will not be posting the answer until 6:30 om tonight EST.  I certainly will post it here.

There are almost 5,000 responses on the page.  And just incase he is right, DS was the first person to say 6.

What kind of radio station is doing this and stating they will reveal the answer?  This isn't like a "What color did we dye the new interns hair?" Where you need to reveal the answer, this is a fairly simple math question that a lot of people get wrong because they don't understand PEMDAS, either because they are bad at math, or because they were taught wrong.

I still don't see what they are gaining from this, revealing the answer will either show them to be stupid, or force them to call a portion of their listening audience math imbeciles.  Neither of these is a good idea.

#### MOM21SON

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##### Re: A math problem.
« Reply #43 on: November 02, 2012, 11:55:51 AM »
well, overnight brought a few more 6's , 7's and 5's.  Tons of ones and the newest trend is 3.5.

The station will not be posting the answer until 6:30 om tonight EST.  I certainly will post it here.

There are almost 5,000 responses on the page.  And just incase he is right, DS was the first person to say 6.

What kind of radio station is doing this and stating they will reveal the answer?  This isn't like a "What color did we dye the new interns hair?" Where you need to reveal the answer, this is a fairly simple math question that a lot of people get wrong because they don't understand PEMDAS, either because they are bad at math, or because they were taught wrong.

I still don't see what they are gaining from this, revealing the answer will either show them to be stupid, or force them to call a portion of their listening audience math imbeciles.  Neither of these is a good idea.

I wasn't aware there had to be a point or somethng to gain. Maybe they are gaining fans due to the high number of responses.  Maybe it's just fun.  There is no requirement to guess.

I find it interesting that there are many different responses and there are several posts stating to people that they are dead wrong for each answer.

I have listened to the station long enough that I am quite sure they will post the answer and the reason for it.

So, if you want to stick around for the answer, what they say will be posted this evening.

BTW, I must have missed your answer, can you share it?