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The math problem breaking the internet


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2018 Sep 26, 6:18pm   3,657 views  30 comments

by Tenpoundbass   ➕follow (7)   💰tip   ignore  

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1   RC2006   2018 Sep 26, 6:28pm  

Isn't it 1?
3   🎂 Tenpoundbass   2018 Sep 26, 6:38pm  

Clearly the answer is firing the Analyst that can't write a proper Algebra equation.
There is no room for assumptions in math.
It's one if you consider to the parenthesis a division, but then why wasn't the 6/2 not written like that?
The answer is 9 if you consider the bracket multiplication.
4   Hircus   2018 Sep 26, 7:01pm  

It's like:

1/2x

is it (1 / 2)x
or 1 / (2x)

I think the first is correct if you follow procedure strictly, even though at first glance I visually feel like "2x" are tightly bound, yielding the second interpretation.


Furthermore, I bet if you write it like
1 / 2x

you'll see more variation of interpretation from people.
5   theoakman   2018 Sep 26, 7:08pm  

IMO, the way it's written, you have to assume there is no parenthesis, but it's a stupid way to write it. My experience in teaching physics and chemistry for 10 years is that you would use a fraction with parenthesis present in the equation rather than a division sign. It's just a dumb way of writing something. That being said, I regularly see students mess up 1/(2*pi) in their calculators and report it as 1.57. Even if it was written correctly, I would still estimate about 40% of the internet would screw it up.
6   anonymous   2018 Sep 26, 7:15pm  

Order of Operations is simple if you simply follow the rules. Carry out the stuff in parenthesis first and then perform the division. The correct answer is one.

The example above should never yield 1.57 if the order of operations were used correctly. Clearly this is (2*π)^-1 which is close to 0.15915.
7   Shaman   2018 Sep 26, 9:38pm  

I’ll agree with the above. This is just a test of order of operations knowledge. Parentheses first.
Answer is 1
8   Blue   2018 Sep 26, 10:35pm  

The given expression is ambiguous which is wrong in math to begin with.
Obviously it can leads to multiple answers.

BE EXPLICIT:
A. 6/2 (1+2) = (6/2)(1+2) = 9.0
B. 6/(2*(1+2)) = 1.0
9   RWSGFY   2018 Sep 26, 10:48pm  

Believe it or not, in Java the answer will be 9:

package foo;

public class Foo {
public static void main(String[] args) {
int x = 6/2*(1+2);
System.out.println("6/2*(1+2) =" + x);
}
}

run:
6/2*(1+2) =9
BUILD SUCCESSFUL (total time: 0 seconds)
10   Allin   2018 Sep 26, 11:36pm  

Java is correct. Order of operation is parenthesis, exponents, mulitiplication & division from left to right.
11   Evan F.   2018 Sep 27, 1:12am  

Lordy, I hope the internet can survive this.
12   curious2   2018 Sep 27, 5:59am  

The answer is currently 9.

A century ago, it would have been 1.

The change results from a change in usage. It isn't really ambiguous, but it can seem arbitrary. One day Pluto was a planet, and the next day it wasn't; Pluto itself had not really changed, but the definition of planet changed. One day the answer to the math problem was 1, and now it is 9.
13   🎂 Tenpoundbass   2018 Sep 27, 6:25am  

Allin says
Java is correct.


It's the same way in C# but if you remove the multiplier operator it would create an error in both languages.

I think it's a problem that was written by someone who made a mistake.
14   Hircus   2018 Sep 27, 6:57am  

Aphroman says
When did this change? I grew up in the era where schools taught that the answer is 1


I was taught PEMDAS, which yields 9. What did they teach you to arrive at 1?
15   RWSGFY   2018 Sep 27, 8:26am  

Aphroman says
curious2 says
The answer is currently 9.

A century ago, it would have been 1.

The change results from a change in usage. It isn't really ambiguous, but it can seem arbitrary. One day Pluto was a planet, and the next day it wasn't; Pluto itself had not really changed, but the definition of planet changed. One day the answer to the math problem was 1, and now it is 9.


When did this change? I grew up in the era where schools taught that the answer is 1


Me too.
16   Patrick   2018 Sep 27, 10:04am  

Moral of the story: don't be shy to use parentheses so make the order of operations clear.
17   curious2   2018 Sep 27, 11:48am  

Aphroman says
When did this change?


Aphroman says
Please excuse my dead aunt sally


Condolences on the loss of your late aunt Sally. Back when I went to school, my dear Aunt Sally remained very much alive, solving math problems. I think she might tell you to solve the parentheses first:

1+2 = 3

Then, she might tell you to do the rest from left to right, because she considered multiplying and dividing as reciprocal operations:

6÷2 = 3

3*3 = 9.

I don't know when Sally died. She seemed hale and hearty when last I saw her.

There are many articles about this problem, and some say different calculators produce different results. Older Texas Instruments calculators are said to produce 1, for example, while newer calculators are said to produce 9. The article I linked above contains quite an argument on the topic, with my favorite comment saying that if you start dividing 6 apples then you can't end up with 9 apples, so the answer must be 1 and not 9. I would actually prefer 1 to be the correct answer, so if anyone can prove that, please go ahead.

Meanwhile, I think the best comments here are that the problem should be written more clearly with nested parentheses:

Patrick says
Moral of the story: don't be shy to use parentheses so make the order of operations clear.
18   EBGuy   2018 Sep 27, 11:55am  

Long live RPN.
19   WookieMan   2018 Sep 27, 11:56am  

Aphroman says
When did this change? I grew up in the era where schools taught that the answer is 1


Lol, who the fuck knows what the schools teach now. I'm not Einstein by any stretch, but was able to accomplish a few calculus courses with a B grade. The shit they send home with my 2nd grader makes my head spin. It legit is fucked up now. Not pertinent to this problem in the OP, just saying I don't know what the fuck they're teaching now.

My math skills have lapsed... well because computers. But if no one knows how to do this shit after the apocalypse, then we have a problem. Who knows, maybe the new way is better and my kid will build rockets or something cool with his ass backwards math.
20   curious2   2018 Sep 27, 12:51pm  

Aphroman says
Give me a real world problem for which this equation would need solved, please


This is actually why I would prefer the answer to be 1. Quoting a poorly written comment disagreeing with the article linked above:

"If I have 6 apples and I want to give this 6 apples on 2 groups of one boy and two girl the answer in one apple for each other. The answer can’t be 9 apple."

In that context though, you would start by dividing the apples into the two groups, and then distribute the apples within each group. Instead of writing the OP equation, you would write two sequential equations: 6/2 = 3, and then 3/(1+2) = 1.

The only context where I can see actually needing to solve this equation as written is in a math test written by a bad "math" teacher.
21   bob2356   2018 Sep 27, 2:11pm  

Allin says
Java is correct. Order of operation is parenthesis, exponents, mulitiplication & division from left to right.


That's what I learned in the 60's. How old are you guys that learned before that?
22   Shaman   2018 Sep 27, 3:31pm  

There are four lights!!!
23   RWSGFY   2018 Sep 27, 3:32pm  

bob2356 says
Allin says
Java is correct. Order of operation is parenthesis, exponents, mulitiplication & division from left to right.


That's what I learned in the 60's. How old are you guys that learned before that?


The world is huge and diverse. Never assume anything. For better or worse some countries in Asia and Europe stuck to the "old" way of teaching math for a long time after US switched.
24   mell   2018 Sep 27, 7:05pm  

Quigley says
There are four lights!!!


lol Picard in chain of commands
25   anonymous   2018 Sep 27, 9:54pm  

42. the answer is always 42
26   bob2356   2018 Sep 28, 5:27am  

DASKAA says

The world is huge and diverse. Never assume anything. For better or worse some countries in Asia and Europe stuck to the "old" way of teaching math for a long time after US switched.


patnetters were raised in europe and asia?
27   Patrick   2018 Sep 28, 7:38am  

Some of them, yes.
28   Shaman   2018 Sep 28, 8:35am  

ford_prefect says
the answer is always 4


Correct, but what is the question?
29   RWSGFY   2018 Sep 28, 8:37am  

bob2356 says
DASKAA says

The world is huge and diverse. Never assume anything. For better or worse some countries in Asia and Europe stuck to the "old" way of teaching math for a long time after US switched.


patnetters were raised in europe and asia?


Is this such a rare thing in this day and age?
30   RWSGFY   2018 Sep 28, 8:39am  

Aphroman says
I was taking maths in Pennsylvania public schools in the 90’s, and i was taught PEMDAS. For this problem, I forgot that you go left to right as a rule once you get to Multiply/Division.

What is the difference between the old way and the new way?


The link provided by curious2 nails it. Basically, the old way was to treat the "÷" sign as "everything after it goes to the lower part of the fraction".

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