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 Elementary Math Fractions, Percentages, Word Problems, Equations, Inequations, Factorization, Expansion

 May 18th, 2012, 05:08 PM #1 Newbie   Joined: May 2012 Posts: 2 Thanks: 0 I'm sure this has been brought here before Hi, 6/2(2+1)= X about 10 people in my office say the answer is 9. A friend of mine and I say is 1 Well I did a search over the internet and most of people say is 9 The way they see it is like this: (6/2) x (2+1)= 3x3=9 My friend and I see it like this 6/(2(2+1))=6/(2x3)= 6/6=1 When I do it in excel and calculators the answer is 9 but is obvious the calculator does not know about omitted parenthesis (which we human know). Therefore, it cannot do the calculation correct. Also if I say the equation is 6/a=x and a=2(2+1)=6. Then 6/a=6/6=x=1
 May 18th, 2012, 05:28 PM #2 Math Team   Joined: Oct 2011 From: Ottawa Ontario, Canada Posts: 14,418 Thanks: 1025 Re: I'm sure this has been brought here before Answer is 9. 6 / (2(2+1)) = 1. What's in brackets is done FIRST: (2 + 1) = 3 Then the division: 6/2 = 3 Then the multiplication: 3 * 3 = 9.
 May 18th, 2012, 06:04 PM #3 Newbie   Joined: May 2012 Posts: 2 Thanks: 0 Re: I'm sure this has been brought here before yes the answer is 9. I did a research and that is the number. thanks,
May 18th, 2012, 06:23 PM   #4
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Re: I'm sure this has been brought here before

Quote:
 Originally Posted by Granrey When I do it in excel and calculators the answer is 9 but is obvious the calculator does not know about omitted parenthesis (which we human know).
We humans do NOT know about omitted parenthesis if they aren't there! There is a difference between understood parenthesis and "omitted" parenthesis. If you had written it out as a fraction like this

$\frac{6}{2(2+1)}$

then there's like an "understood" parenthesis in the denominator.

But you did not write it like that. You wrote it out on one line, meaning you have to include those parenthesis if that is what you mean, and no one could assume there was supposed to be something there. So no, we don't have the ability to know about "omitted" parenthesis.

In fact, this causes problems around here all the time cause we never know what someone "meant" to do.

 June 19th, 2012, 07:20 AM #5 Newbie   Joined: Apr 2012 Posts: 18 Thanks: 0 Re: I'm sure this has been brought here before um i think the the order should be 1) brackets (B) 2)of (O) 3)divide (D) 4)multiply (M) 5)add (A) 6)subtract (S)
June 19th, 2012, 12:12 PM   #6
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Re: I'm sure this has been brought here before

Quote:
 Originally Posted by Granrey Hi, 6/2(2+1)= X ...
I, too, have done some research and concluded that
Quote:
 Only a jackass would write such an expression!
But seriously. This was a big trolling event on the internets a while back... Maybe I can find a link.
Ah.
viewtopic.php?f=13&t=20148&p=79150#p79150

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