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Math is not a democracy
(lemmy.world)
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this post was submitted on 18 Dec 2025
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This isn’t even math, just convention on rules for order of operations.
The one response you got was just like, "But there's just ONE rule." totally missing your point.
Order of operations only has one rule: Bedmas (or pemdas if you're not from north america)
Huh it was always pemdas in both highschool and college in new England for me.... they were also always parentheses. 'Brackets' only reffered to '[ ]' which were reserved for matrices or number sets, eg 2*[2,5,8]+2= [6,12,18]
I think canadians call ( ) brackets in math
If you look at the arguments on math forums, you'll see that there isn't just one rule.
It is a convention, and different places teach different conventions.
Namely, some places say that
PEDMASis a very strict order. Other places say that it isPE D|M A|S, where D and M are the same level and order is left-to-right, and same with addition vs subtraction.And others, even in this post, say it's
PEMDAS, which I have heard before."Correct" and "incorrect" don't apply to conventions, it's simply a matter of if the people talking agree on the convention to use. And there are clearly at least three that highly educated people use and can't agree on.
But they all teach the same rules
Which is totally fine and works
Which is also totally fine and works
Also totally fine and works
No-one has to agree on any convention - they can use whatever they want and as long as they obey the rules it will work
Educated people agree that which convention you use doesn't matter.
That's not true Here is an example:
8÷2x4
PEMDAS: 8÷2x4 = 8÷8 = 1
PEDMAS: 8÷2x4 = 4x4 = 16
PE M|D A|S: 8÷2x4 = 4x4 = 16
And thats not even getting into juxtaposition operations, where fields like physics use conventions that differ from most other field.
but you're missing the point. It could be SAMDEP and math would still work, you'd just rearrange the equation. Just like with prefix or postfix notation. The rules don't change, just the notation conventions change. But you need to agree on the notation conventions to reach the same answer.
Yes it is
Yep.
Nope. PEMDAS: 8x4÷2 = 32÷2 = 16. What you actually did is 8÷(2x4), in which you changed the sign in front of the 4 - 8÷(2x4)= 8÷2÷4 - hence your wrong answer
Yep, same answer regardless of the order 🙄
Which I have no doubt you don't understand how to do those either, given you don't know how to even do Multiplication first in this example.
Nope! The obey all the rules of Maths. They would get wrong answers if they didn't
No, you are...
No it can't because no it wouldn't 😂
Says someone who didn't rearrange "PEMDAS: 8÷2x4 = 8÷8 = 1" and got the wrong answer 😂
Hence why "PEMDAS: 8÷2x4 = 8÷8 = 1" was wrong. You violated the rule of Left Associativity
Ok, then explain prefix and postfix, where these conventions don't apply. How can these be rules of math when they didn't universally apply?
The order of operations tells us how to interpret an equation without rearranging it. When you pick a different convention, you need to rearrange it to get the same answer. What you did was rearrange the equation, which you can only do if you are already following a specific convention.
All conventions can produce the correct answer, when appropriately arranged for that convention, because the conventions are not laws of mathematics, they are conventions.
They obey the laws of math. Conventions aren't laws of math, they're conventions. And a quick Google search will tell you that not everyone puts juxtaposition at a higher precedent than multiplication; it's a convention. As long as people are using the same convention, they'll agree on an answer and that answer is correct.
You can be mean all you like, that doesn't change the nature of conventions
The conventions don't apply, the rules still apply. Maths notation and the rules of Maths aren't the same thing.
The rules do universally apply 🙄
Yep, and you showed you don't know the rules 🙄
Not necessarily, though it makes it easier (but also leads a lot of people to make mistakes with signs, as you found out 😂 )
To show you how to correctly do "Multiplication first". 🙄
Which you didn't, hence why you ended up with a wrong answer. 🙄 There is no textbook which says put the multiplication in Brackets if doing "Multiplication first", none.
And putting the Multiplication inside Brackets isn't a convention anywhere 🙄
Yep, and you ignored both, hence your wrong answer 🙄
And a quick look in the Google support forum will show you many people telling them that is wrong, and Google just closes the incident 🙄
No it isn't. It's against the rules. 🙄 Again, you won't find this alleged "convention" in any Maths textbook
Unless they disobeyed the rules, in which case they are all wrong 🙄
And you can be as ignorant of the rules and conventions of Maths as much as you want, and it's not going to change that your answer is wrong 🙄
Yeah, you clearly don't even know what a convention is, and what are math conventions and math "rules" as you put it.
You're wrong, and even a 2 minute Google search would show you that and explain why. I'm done being Google for you when you're not willing to Google it yourself.
Says person who actually doesn't know the difference, as per Maths textbooks
oh no! you better start contacting all the textbook publishers and tell them that all Maths textbooks are wrong 😂
Even a 2 minute Google search will bring up Maths textbooks which prove that Google is wrong 🙄
Maths teachers don't use Google - that's what Maths textbooks are for
says person who was unwilling to use Google to find Maths textbooks 🙄
Wikipedia
What's that? You don't trust Wikipedia?
Ok, you've yet to explain why notations like prefix and postfix dont need these "rules".
If they were rules of mathematics **itself** how could they only apply to certain notations?
isn't a Maths textbook 🙄 far out, did you learn English from Wikipedia too? You sure seem to have trouble understanding the words Maths textbook
The site that you just quoted which is proven wrong by Maths textbooks, THAT Wikipedia?? 🤣🤣🤣
Umm, they do need the rules! 😂
They don't, they apply to all notations 🙄
I love how confident you are about something you clearly have no knowledge of.
Adorable.
Well, you made a good effort. At least if we're judging by word count.
says person confidently proving they have no knowledge of it to a Maths teacher 🤣
from Maths textbooks, which for you still stands at 0
To a "maths teacher"
Yeah sure
A "teacher" who doesn't know that all lessons are simplifications that get corrected at a higher level, and confidentiality refers to children's textbook as an infallible source of college level information.
A "teacher" incapable of differentiating between rules of a convention and the laws of mathematics.
A "teacher" incapable of looking up information on notations of their own specialization, and synthesizing it into coherent response.
Uh huh, sounds totally legit
As opposed to a Maths teacher who knows there are no corrections made at a higher level. Go ahead and look for a Maths textbook which includes one of these mysterious "corrections" that you refer to - I'll wait 😂
A high school Maths textbook most certainly is an infallible source of "college level" information, given it contains the exact same rules 😂
Well, that's you! 😂 The one who quoted Wikipedia and not a Maths textbook 😂
You again 😂 Wikipedia isn't a Maths textbook
Man, this whole post has been embarrassing for you. Oof.
I can't help but notice youve once again failed to address prefix and postfix notations.
And that you've not actually made any argument other than "nuh uh"
Not to mention the other threads you've been in. Yikes.
We can all tell you're not a maths teacher.
Nope. I'm the only one who has backed up what they've said with Maths textbooks 🙄
What is it that you want addressed?
Backed up by Maths textbooks 🙄
Says person who actually isn't a Maths teacher, hence no textbooks 😂
Your argument you haven't made is backed up by math textbooks you haven't provided written for children.
How can that specific order of operations be a law of mathematics if it only applies to infix notation, and not prefix or postfix notations? Laws of mathematics are universal across notations.
Show me a textbook that discusses other notations and also says that order of operations is a law of mathematics.
You don't have it, and you also aren't a maths teacher, or a teacher at all. Just because you say it a lot doesn't make it true.
That's quite a word salad. You wanna try that again, but make sense this time?
If I didn't make it then it's not my argument, it's somebody else's 😂
as well as the textbooks I have provided 😂
All my textbooks are for teenagers and adults
I already addressed that here. I knew you were making up that I hadn't addressed something 🙄
Correct, they do.
If you think it's not a Law, then all you have to do is give an example which proves it isn't. I'll wait
You mean you don't have a counter-example which proves it's not a Law
says liar
You know you just saying it's not true doesn't make it not true, right? 🤣🤣🤣
BTW, going back to when you said
Here it is from a textbook I came across this week which proves I was right that you did it wrong 😂
Therefore, doing Multiplication first for 8÷2x4 is {(8x4)÷2}, not 8÷(2x4) - whatever you want to do first, you write first - exactly as I told you to begin with 🙄
In your screenshot of a textbook, they refer to it as a convention twice.
And you still haven't explained prefix or postfix notation not having order of operations.
Get rekd idiot
Left to right is a convention, yes, doing Multiplication and Division before Addition and Subtraction is a rule 🙄
For the 3rd time it does have order of operations 🙄 You just do them in some random order do you? No wonder you don't know how Maths works
says person who doesn't know the difference between conventions and rules, and thinks postfix notation doesn't have rules 🙄
A claim entirely unsupported by the textbook example you provided. Nowhere does it say that one is a convention but not the other, it only says that removing brackets changes the meaning in some situations, which is fully within the scope of a convention.
There you go again, just admitting you don't know what postfix and prefix notations are.
If you're ordering your operations based what the operator is, like PEDMAS, then what you're doing isn't prefix or postfix.
I'll tell you what, here is a great free article from Colorado State university talking about prefix, postfix, and infix notations.
Note how it says the rules about operator precedence are for the notation which itself is a convention, as all notations are, and how prefix and postfix don't need those rules
How embarrassing for you.
Here are some more materials:
But to top it all off, if this was truely a law of mathematics, then show me a proof, theorem, or even a mathematical conjecture, about order of operations.
says person who pointed out to begin with it was talking about conventions. BWAHAHAHAHAHA! I even underlined it for you. Ok, then, tell me which convention exactly they are talking about if it isn't left to right 😂
It quite clearly states that left to right is a convention 🙄
"the other" wasn't even the subject at hand. 🙄 Here you go then...
But not within the scope of rules 🙄
There you go again not being able to say what the RULES for them are! 🤣🤣🤣 I admitted nothing of the kind by the way. I already told you 3 times they obey the same rules 🙄
It's pretty rubbish actually - finding a blog post by someone as ill-informed as you doesn't make it "great". Note that I always cite Maths textbooks and thus have no need to ever quote blog posts? 😂
Because (sigh) the same rules apply to all notations 🙄
Yep, and are separate to the rules, which are the same for all notations
Nope. Doesn't say that anywhere. Go ahead and screenshot the part which you think says that. I'll wait
Doesn't say that either. 🙄 Again, provide a screenshot of where you think it says that
BTW this is completely wrong...
"Infix notation needs extra information to make the order of evaluation of the operators clear" - Anyone who knows the definitions of the operators and grouping symbols is able to derive the rules for themselves, no need for any "extra information" 🙄
"For example, the usual rules for associativity say that we perform operations from left to right" - The thing we just established is a convention, not rules 🙄
"so the multiplication by A is assumed to come before the division by D" - Which we've already established can be done in any order 🙄
No, you actually. You know, the person who can't find a single textbook that agrees with them 😂
NONE of which were Maths textbooks, NOR Maths teachers 😂
None of which are actually ambiguous. He should've looked in a Maths textbook before writing it 😂
"the 48/2(9+3) question" - 48/2(9+3)=48/(2x9+2x3), per The Distributive Law, as found in Maths textbooks 😂
Did you even read it?? Dude doesn't even know the definition of Terms, ab=(axb) 🤣🤣🤣
"Without an agreed upon order" - Ummm, we have proven rules, which literally anyone can prove to themselves 😂
"There is no mathematical reason for the convention" - There are reasons for all the conventions - talk about admitting right at the start that you don't know much about Maths 🙄
It only explains the mnemonics actually, not why the rules are what they are. 🙄
Did you read it?? 🤣🤣🤣
"The order of operations — as Americans know it today — was probably formalized in either the late 18th century" - Nope! Way older than that 🙄
It actually did a better job than all of the university blogs you posted! 🤣🤣🤣
Because not Maths textbooks, duuuuhhhh 🤣🤣🤣
Which it is as per Maths textbooks 🤣🤣🤣
The proof is it's the reverse operation to Factorising, thus must be done first 🙄
But since you hate Maths textbooks, go ahead and search for "reverse operation of distributive law" and let me know what you find. I'll wait 🤣🤣🤣
That's some awful impressive goalpost shifting. Gold medal mental gymnastics winner.
And here you are, still unable to explain why prefix and postfix notation don't have an operator precedence. I'm still waiting.
They literally don't, and I defy you to show me a single source that tells you that prefix or postfix notation use PEDMAS. I'll even take Quora answers.
Heck, I'll even take a reputable source talking about prefix/postfix that doesnt bring up how order of operations isn't required for those notations.
Right here:
Which you attempt to retort with
But then you go on to say something to the effect of "anyone who knows the rules can the extra information". Which is both unsubstantiated given the long history of not having PEDMAS, but also kind of a nothingburger.
It's literally the whole thing. Did you notice how they never discuss the need for operator precedence, or use operator precedence?
Build for me a prefix or postfix equation that you think is changed by adding parentheses (eg overriding the natural order of operations), and then go ahead and find a prefix or postfix calculator and show me the results of removing those parentheses.
If you read the rules for those notations, you'll see pretty clearly that operator precedence is purely positional, and has nothing to do with which operator it is.
No, you've show a screenshot from a random PDF. What math textbook and what edition is it?
The fact you think that factorization has to do with order of operations is shocking.
Yes the multiplication is done first, but not because PEDMAS. The law is about converting between a sum of a common product and a product of sums. No matter how you write them, it will always be about those things, so the multiplication always happens first. It doesn't depend on PEDMAS because without PEDMAS you'd simply write the equation differently and factorization would still work.
It's crazy that you're not able to distinguish between mathematical concepts and the notation we use to describe them.
But putting that aside, that's not a proof of PEDMAS.
If PEDMAS is an actual law, then there will be a formal proof or theorem about it. There are proofs for 1+1, if PEDMAS is a law then there will be an actual proof specifically about it. Not just some law and then you claim it follows that PEDMAS is true, an actual proof or theorem, or an textbook snippet explain how it is an unprovable statement.
BWAHAHAHAHAHAHA! Says person refusing to acknowledge that it's in textbooks the difference between conventions and rules 🤣🤣🤣
Yep, I know you are. That's why you had to post known to be wrong blogs, because you couldn't find any textbooks that agree with you 🤣🤣🤣
Speaking of goalpost shifting - what happened to they don't have rules?? THAT was your point before, and now you have moved the goalposts when I pointed out that the blog was wrong 🤣🤣🤣
says person who has still not posted any textbook at all with anything at all that agrees with them, to someone who has posted multiple textbooks that prove you are wrong, and now you are deflecting 🤣🤣🤣🤣
they literally *do., That's why the rules get mentioned once at the start of the blog - it's the same rules duuuhhh!!! 🤣🤣🤣
PEMDAS isn't the rules, it's a convention
I won't take anything but textbooks, and you've still come up with none
That's exactly what the blog you posted does. I knew you hadn't read it! BWAHAHAHAHAHAHAHA! 🤣🤣🤣 I'll take that as an admission of being wrong then
of a Maths textbook, with the name of the textbook in the top left, and the page number also in the top left. 🤣🤣🤣
Yep, says nothing about operator precedence being tied to the notation, exactly as I just said, so that's a fail from you then
derive the rules is what I said liar. The only thing you need to know is the definition of the operators, everything else follows logically from there.
The order of operations rules are way older than PEMDAS. It even says it in one of the blogs you posted that PEMDAS is quite recent, again showing you didn't actually read any of it. 🙄
Nothing random about it. The name of the textbook is in the top left. Go ahead and search for it and let me know what you find. I'll wait 🤣🤣🤣
So, you're telling me you don't know how to look at the name of the PDF and search for it?? 🤣🤣🤣 I can tell you now it's the #1 hit on Google
says person revealing they don't know anything about order of operations 🤣🤣🤣 Make sure you let all the textbook authors know as well 🤣🤣🤣
No, Brackets are done first.
Nope. That's the Distributive Property, and yes indeed, the Property has nothing to do with order of operations, but the Distributive Law has everything to do with order of operations.
The Property will, the Law isn't
No, Brackets are always done first
says person who doesn't even know the difference between a Property and a Law, and, as far as I can tell, have never even heard of The Distributive Law, given they keep talking about the Property
Right, it's a proof of the order of operations rules for Brackets 🙄
It isn't, it's a convention
It's true by definition. There's nothing complex about it. Just like ab=(axb) is true by definition
It isn't, it's a convention. Not sure how many times you need to be told that 🙄
You mean like textbook snippets stating that The Distributive Law is the reverse operation to Factorising?? See above 🤣🤣🤣
THANK YOU. this is what I've been trying to tell you the entire fucking time. PEMDAS is not a law, its a convention.
but just in case you decide to go back on that, and since you seem to be obsessed with the idea that all notations adhere to PEMDAS - let me blow your mind:
here is the distributive law, written in the 3 notations we've been talking about:
prefix:
*a+bc = +*ab*acinfix:
a(b+c) = ab+acpostfix:
abc+* = ab*ac*+(not using juxtaposition multiplication for prefix/postfix for clarity)
so where does PEDMAS get involved in prefix or postfix notations?
regarding your textbook being the first google result... are you referring to the textbook from 1913? for someone talking about the importance of textbooks, thats a really strange choice. I can't find another with the same name and author of either Coll or Rich.
and hilariously, if you look at that text book, on page 90 it says the following: