Poll: 6÷2(1+2)

[N19h7m4r3]

Post #1239

Successful troll is successful

The original troll posted a facebook poll about it.

Last I checked it was over 88,000 posts and increasing.
Best troll I have ever seen

 

[muon]

The original troll posted a facebook poll about it.

Last I checked it was over 88,000 posts and increasing.
Best troll I have ever seen

88,000 posts plus hundreds of thousands of comments

 

[FoxEye]

The answer would be different if there was a multiplication sign between the bracket and the second term as you would be calculating from left to right.

Source?

a*b
ab
a*(b)
(a)(b)

All mean the same thing, surely?

 

[BetaNumeric]

Out of interest, what sort of stuff do you do now?

Maths-wise anything from functional analysis and differential geometry through to optimisation and machine learning. The stuff I've been involved in applying that to I can't be too specific but the company I'm in has had or has contracts with the Ministry of Defence, energy sector companies and the European Space Agency (ESA). I've done stuff relating to all of those. It's slightly cringe-worthy but due to something I was involved with for ESA I can literally call myself a rocket scientist . I do miss doing theoretical physics at times but now I'm doing applicable stuff, even when I'm doing abstract maths

 

[gambitt]

Maths-wise anything from functional analysis and differential geometry through to optimisation and machine learning. The stuff I've been involved in applying that to I can't be too specific but the company I'm in has had or has contracts with the Ministry of Defence, energy sector companies and the European Space Agency (ESA). I've done stuff relating to all of those. It's slightly cringe-worthy but due to something I was involved with for ESA I can literally call myself a rocket scientist . I do miss doing theoretical physics at times but now I'm doing applicable stuff, even when I'm doing abstract maths

Christ almighty. Disagreeing with you about maths would be like Delboy telling Richard Branson how to run a business. Doesn't stop them from trying though...

Now that you have your PhD do you call yourself Dr? If I recall you are only in your mid to late 20's, yes?

 

[BetaNumeric]

I can call myself Dr and my parents (both of whom are also doctors, though one is medical, the other academic) tell me to put it on things like bank forms and car insurance because it can be useful for cheaper rates. Generally though I rarely have any occasion to say "Hi, I'm Dr....". When a potential client visits the company we'll each be introduced as "This is Dr...." (everyone I work with day to day has a PhD) but that's a way of putting forth a good image. I don't use it when doing things like booking plane tickets. My dad never does and my mum has actually had the dreaded tap on the shoulder and "You're a doctor, aren't you?" during a flight. I'm 27 and only did the graduation ceremony last July, though I'd passed the viva etc about this time last year.

 

[ordinaryjoe]

Problem is, without knowing the expression writers intentions, you might get the "right" answer to the wrong question.

But then surely, that is the question maker's mistake. It is like someone saying "if x=1 what's the value of 2x^2" and you answer 2, you are correct - even if they meant to ask "if x=1 what's the value of (2x)^2"
You have given the correct answer - even if they asked the question in a way different to what they were trying to imply. There aren't 2 correct answers to these basic maths questions. That would just cause problems. Maths has rules to prevent this, and these are the rules you see with decent modern calculators and wolfram alpha.

I find it hard to believe you were given a question where you needed to use the 'left to right rule'.

24÷3÷2 would never be written by anyone semi-numerate.

It was a test when we first started the course to see who needed extra maths teaching outside of normal lectures. This question was obviously intended to see who knew which orders to do the various operations in, and at that point, I got it wrong and have since learnt. My maths lecturers were certain enough to actually test us on it to check that we knew too and considered it important to check that people know which order to do operations in.

 

[FoxEye]

Christ almighty. Disagreeing with you about maths would be like Delboy telling Richard Branson how to run a business. Doesn't stop them from trying though...

With all due respect (and I do have a lot of respect for those who have pushed themselves through academia), I find it impossible to agree with anything you say gambitt. Or in this case imply.

First is that everyone who is a math graduate, or everyone who is a specialist in some field of math, is going to have a definitive answer on hand for such a simple and abnormal problem as the OP posted. I think that video of the ring theorist demonstrates nicely that in general people are only 100% prepared to talk about the things they specialise in/deal with in their field of work. Poor guy had never even heard of bodmas...

Second is that anyone should feel unjustified in questioning or debating with a person of greater learning than themselves. Even the most academically brilliant person isn't going to know everything, or have perfect recall of everything they've learned.

And gambitt, your attitude makes me want to argue with you, even if you are right and I'm 100% wrong, because you are so infuriatingly smug

Anyway, if bodmas is not a convention, or is not applicable even in such a simple problem as the OP posted, then WHY TEACH IT?

It's not like we're saying "bodmas works with infant level math but no higher". The problem posted _was_ infant level math, so if it doesn't work there, surely it shouldn't be taught at all?

There are still questions here I don't feel have been answered.

 

[Pinkribbonscars]

Anyway, if bodmas is not a convention, or is not applicable even in such a simple problem as the OP posted, then WHY TEACH IT?

Because it is easiest to teach simple rules. Most students will not need to know any more than that, those that do just have to learn that it is simplified.

Same reason GCSE students are told the electron structure of an atom, only to find out it is a simplification at A-Level, and then to find out again that that was a simplification at degree level.

 

[FoxEye]

Because it is easiest to teach simple rules. Most students will not need to know any more than that, those that do just have to learn that it is simplified.

Simple rules for simple problems, yes. But the OPs problem was simple, yes. And the simple rules are being thrown out for this simple problem, yes?

So really, of what use were the simple rules for the simple problem? None, they say.

We cannot teach kids simple rules if the most simple of problems cannot be solved by said simple rules. Or if those simple rules make legitimate solutions appear incorrect.

That wouldn't be helping our kids at all.

 

[ordinaryjoe]

Because it is easiest to teach simple rules. Most students will not need to know any more than that, those that do just have to learn that it is simplified.

Same reason GCSE students are told the electron structure of an atom, only to find out it is a simplification at A-Level, and then to find out again that that was a simplification at degree level.

But surely it's easier to not teach a rule that doesn't exist at all than to teach a rule which is wrong.

Maths avoids ambiguity - there is only 1 right answer to a question. The answer isn't necessarily 1 number (e.g. root 4 is either -2 or 2, but "-2 or 2" is 1 answer - they are both simultaneously correct). Why would maths be left in a way in which such a simple question can have more than 1 different answer? That is why the 'left to right' rule is taught, and not only at primary schools - by Maths lecturers in Universities.

 

[Gzero]

But surely it's easier to not teach a rule that doesn't exist at all than to teach a rule which is wrong.
Maths avoids ambiguity - there is only 1 right answer to a question. The answer isn't necessarily 1 number (e.g. root 4 is either -2 or 2, but "-2 or 2" is 1 answer - they are both simultaneously correct). Why would maths be left in a way in which such a simple question can have more than 1 different answer? That is why the 'left to right' rule is taught, and not only at primary schools - by Maths lecturers in Universities.

Hmm, then how do you teach some one the properties of light?

Why do 2 systems exist for Matrices? Which is better RH or LH?

 

[BetaNumeric]

Poor guy had never even heard of bodmas...

Firstly I think it might be called something else in other countries. I say this because someone posted a YouTube video or picture whose title uses a different acronym to BODMAS.

Secondly the last time I heard 'BODMAS' was in primary school. By the time you get to degree it should be second nature to write things in a way to be unambiguous. Whenever someone writes something in an ambiguous way it is invariably because they don't know the proper practice and thus you have to ask them for clarification, regardless of whether or not there is a specific rule for interpreting ambiguous expressions.

The maths of university level has a very different structure and feel to it than stuff at school, it isn't just lots of adding and dividing of big numbers (amazingly some people think that's what it is). All the time new notation and expressions are introduced to you and some of them are completely unlike anything seen before. Like I said when I first started replying to this thread, I haven't used the ÷ sign since school, possibly even primary school. That shows that this sort of question is not aimed at highly mathematical people but is more "Here's an expression you'd expect to see in an 8 year olds book, what does it mean?". The answer? "Ask the 8 year old", not "Ask a ring theorist".

My next question, in the same vein as previous ones, is how many people before this thread even knew such a thing as a 'ring theorist' existed in mathematics? And how many of them know what a mathematical ring is?

Second is that anyone should feel unjustified in questioning or debating with a person of greater learning than themselves. Even the most academically brilliant person isn't going to know everything, or have perfect recall of everything they've learned.

Sure, if someone doesn't give you an answer which you feel is appropriate then you should enquire further. But there's a fine line between healthy scepticism and just denial. One of the hallmarks of being intellectually honest and rational is being able to say "Okay, you've given an answer and I admit I do not understand it. As such I will accept your answer is the view of those in the know but I cannot wrap my head around it".

Unfortunately such attitudes on the internet are very few and far between when it comes to maths and science. We all do it every time we go to the doctors, the human body is a very complicated thing and we accept, almost without question, what a doctor tells us. Maths is as complicated as biology (please, let's not start a biologists vs mathematicians thing) but for some reason people form very strong views about mathematics they don't understand, as if because they remember using the ÷ sign 20 years ago then the comments of a ring theorist can just be pushed aside or hold as much weight as their own.

Though I'm not pointing specific fingers I wonder how many people in this thread who formed a strong view on the matter have done any maths since leaving school? How many of them would have no problem shrugging and saying "Okay, turns out I was wrong". A good scientist (a good rational person even) should be willing to say "I was wrong". I can't think of anyone I've worked with who at some time or another has had to say that, myself included. It's the nature of science but so many people online who proclaim themselves competent at science can't say it.

It is useful and applicable and its the thing which becomes second nature. I would never write 1/2/3 because I instinctively feel there's something wrong with that. However, humans are fallible and in my experience whenever someone puts down something which doesn't immediately and obviously have a clear meaning you have to ask them because the mistake they have made might not be what you think they have done, as that assumes they are thinking in the same manner as you.

It's not like we're saying "bodmas works with infant level math but no higher". The problem posted _was_ infant level math, so if it doesn't work there, surely it shouldn't be taught at all?

Infants are the ones most likely not to explain themselves and not to write things following rules older people have more experience with.

If that expression, somehow, appeared in a mathematics paper then you'd have the line before and the line after and so you'd know what it meant.

There are still questions here I don't feel have been answered.

Like what?

I seriously don't see the point in people investing time trying to decipher what is basically an expression someone has deliberately constructed to look dubious. If such an expression appeared in a paper submitted to a journal it would be flagged for confirmation and a comment made about poor notation. The reviewer wouldn't spend a week searching for a particular rule to use to interpret it. This is because a paper should be easily readable (when aimed at the appropriate audience) and a good reviewer will point out everything from poor grammar through to dubious notation right through to fundamental flaws making the paper worthless. And then we're back to the 'someone should be willing to say "I'm wrong"' thing.

That is why the 'left to right' rule is taught, and not only at primary schools - by Maths lecturers in Universities.

And which rule is that? My first instinct is to scan through expressions right to left as it is often easier to compose functions and matrix operators in the manner and to understand the effect of linear operators on their arguments (like a sequence of matrices applied to a vector).

Mathematicians at universities have bigger fish to fry than trying to decipher poor notation. A rule often used in marking is that if it isn't clear what you're trying to say then you don't get the mark. Despite the stereotype, for mathematicians (as well as anyone else) there is a mild important on being able to communicate your thoughts clearly. Very few mathematicians in history have warranted another sifting through their work (typically after their death) to decipher their work. Some kid writing primary school level expressions doesn't make the cut.

 

[Vonhelmet]

The so called 'primary school left to right rule' is used in degree level maths
24÷3÷2 for example highlights the point. What would you evaluate the answer to be? Without the left to right rule, you could easily get 16.

Heh. If I got that question in an exam I'd be writing down both answers and stating that I found it ambiguous and asking for clarity. Bodmas can go hang. I wouldn't trust anyone asking that question like that to even know what answer they were after.

 

[Haircut]

Maths-wise anything from functional analysis and differential geometry through to optimisation and machine learning. The stuff I've been involved in applying that to I can't be too specific but the company I'm in has had or has contracts with the Ministry of Defence, energy sector companies and the European Space Agency (ESA). I've done stuff relating to all of those. It's slightly cringe-worthy but due to something I was involved with for ESA I can literally call myself a rocket scientist . I do miss doing theoretical physics at times but now I'm doing applicable stuff, even when I'm doing abstract maths

Sounds like interesting stuff, was wondering if you were doing any physics stuff, but from your reply I guess not.
You get a lot of respect from me for doing what you do. I thought I loved maths as far as A-Level, but my degree just drained any enthusiasm I ever had for the subject.

 

[BetaNumeric]

Sounds like interesting stuff, was wondering if you were doing any physics stuff, but from your reply I guess not.

Depends what you mean by physics. I often do stuff which describes physical systems but I don't do physics in the sense of hands on experiments.

I thought I loved maths as far as A-Level, but my degree just drained any enthusiasm I ever had for the subject.

It happens to a lot of people, particularly in the way degree maths differs so much from school maths in its form and structure. Continues on pass degree too. Some of the people I did my PhD who had been really enthusiastic initially realised within a year that they weren't enjoying it. Something about the gear crunching change in a pace from learning about the life works of 50 geniuses every course/term to suddenly being faced with a problem you have to solve which can't be looked up in a book.

What are you doing now? Something vaguely maths related or did you get put off it enough to not want to do anything mathsy?

 

[FoxEye]

long explanation

Well, that's good enough for me.

It's not admitting I was wrong that's going to upset up; rather admitting that gambitt was right

That's like being KO'd in the first round by a midget in a dress!

 

[Deadbeat]

Well, that's good enough for me.

It's not admitting I was wrong that's going to upset up; rather admitting that gambitt was right

That's like being KO'd in the first round by a midget in a dress!

To be fair, it's more like going toe to toe with a midget in a dress for 8 or 9 rounds before his 7ft hulking fan jumps into the ring and squashes you flat

 

[gambitt]

Which is worse - being a midget in a dress or being unable to put one away after going 8 or 9 rounds?

 

[Haircut]

It happens to a lot of people, particularly in the way degree maths differs so much from school maths in its form and structure. Continues on pass degree too. Some of the people I did my PhD who had been really enthusiastic initially realised within a year that they weren't enjoying it. Something about the gear crunching change in a pace from learning about the life works of 50 geniuses every course/term to suddenly being faced with a problem you have to solve which can't be looked up in a book.

What are you doing now? Something vaguely maths related or did you get put off it enough to not want to do anything mathsy?

I work as a software developer now - in the financial industry, so I do some stuff that is vaguely mathematical.
Even that is mostly just simple arithmetic with a few numerical methods though, so nothing particularly taxing mathematically.

I have to say out of the people I keep in touch with from my course most seemed to have similar opinions to me about carrying on in the maths world.