Some people insist there’s no “correct” order for the basic arithmetic operations. And worse, some people insist the correct order is parenthesis first, then left to right.
Hopefully you can see where their confusion might come from, though. PEMDAS is more P-E-MD-AS. If you have a bunch of unparenthesized addition and subtraction, left to right is correct. A lot of like, firstgrader math problems are just basic problems that are usually left to right (but should have some extras to highlight PEMDAS somewhere I’d hope).
So they’re mostly telling you they only remember as much math as a small child that barely passed math exercizes.
True, but as with many things, something has to be the rule for processing it. For many teachers as I’ve heard, order of appearance is ‘the rule’ when commutative properties apply. … at least until algebra demands simplification, but that’s a different topic.
No, you completely misunderstood my point. My point is not to describe all valid interpretations of the commutative property, but the one most slow kids will hear.
OFC the actual rule is the order doesn’t matter, but kids that don’t pick up on the nuance of the commutative property will still remember, “order of appearance is fine”.
Yes thank you! If you have a sum it is really great to order it in a way that makes it better to ad in your head and i think that lots of people do that without thinking about it.
X=2+3+1+6+2+4+7+5
X=2+3+5+4+6+7+1+2
X=5+5 + 10 +7+1+2
X=10 + 10 + 7+3
X=10 + 10 + 10
I did not flip any signs, merely reversed the order in which the operations are written out. If you read the right side from right to left, it has the same meaning as the left side from left to right.
Hell, the convention that the sign is on the left is also just a convention, as is the idea that the smallest digit is on the right (which should be a familiar issue to programmers, if you look up big endian vs little endian)
If that’s your idea of reversing the order, then you’re not talking about the same thing as [email protected]. They’re talking about the order of operations and the associativity/commutativity property. You’re talking about the order of the symbols.
Huh I just remembered the orders of arithmetic but parentheses trump all so do them first (I use them in even the calculator app). Mean I assume that’s that that says but never learned that acronym is all. Now figuring out categories of words;really does my noodle in sometimes. Cause some words can be either depending on context. Math when it’s written out has (mostly) the same answer. I say mostly because somewhere in the back of my brain there are some scenarios where something more complicated than straight arithmetic can come out oddly but written as such should come out the same.
I mean, arithmetic order is just convention, not a mathematical truth. But that convention works in the way we know, yes, because that’s what’s… well… convention
The rules are socially agreed upon. They are not a mathematical truth. There is nothing about the order of multiple different operators in the definition of the operators themselves. An operator is simply just a function or mapping, and you can order those however you like. All that matters is just what calculation it is that you’re after
Just because a definition of an operator contains another operator, does not require that operator to take precedence. As you pointed out, 2+3*4 could just as well be calculated to 5*4 and thus 20. There’s no mathematical contradiction there. Nothing broke. You just get a different answer. This is all perfectly in line with how maths work.
You can think of operators as functions, in that case, you could rewrite 2+3*4 as add(2, mult(3, 4)), for typical convention. But it could just as well be mult(add(2, 3), 4), where addition takes precedence. Or, similarly, for 2*3+4, as add(mult(2, 3), 4) for typical convention, or mult(2, add(3, 4)), where addition takes precedence. And I hope you see how, in here, everything seems to work just fine, it just depends on how you rearrange things. This sort of functional breakdown of operators is much closer to mathematical reality, and our operators is just convention, to make it easier to read.
Something in between would be requiring parentheses around every operator, to enforce order. Such as (2+(3*4)) or ((2+3)*4)
Isn’t a Maths textbook, and has many mistakes in it
Just because a definition of an operator contains another operator, does not require that operator to take precedence
Yes it does 😂
2+3x4=2+3+3+3+3=14 by definition of Multiplication
2+3x4=5x4=20 Oops! WRONG ANSWER 😂
As you pointed out, 2+34 could just as well be calculated to 54 and thus 20
No, I pointed out that it can’t be calculated like that, you get a wrong answer, and you get a wrong answer because 3x4=3+3+3+3 by definition
There’s no mathematical contradiction there
Just a wrong answer and a right one. If I have 1 2 litre bottle of milk, and 4 3 litre bottles of milk, even young kids know how to count up how many litres I have. Go ahead and ask them what the correct answer is 🙄
Nothing broke
You got a wrong answer when you broke the rules of Maths. Spoiler alert: I don’t have 20 litres of milk
You just get a different answer
A provably wrong answer 😂
This is all perfectly in line with how maths work
2+3x4=20 is not in line with how Maths works. 2+3+3+3+3 does not equal 20 😂
add(2, mult(3, 4)), for typical
rule
But it could just as well be mult(add(2, 3), 4), where addition takes precedence
And it gives you a wrong answer 🙄 I still don’t have 20 litres of milk
And I hope you see how, in here, everything seems to work just fine
No, I see quite clearly that I have 14 litres of milk, not 20 litres of milk. Even a young kid can count up and tell you that
it just depends on how you rearrange things
Correctly or not
our operators is just convention
The notation is, the rules aren’t
Something in between would be requiring parentheses around every operator, to enforce order
No it wouldn’t. You know we’ve only been using brackets in Maths for 300 years, right? Order of operations is much older than that
Such as (2+(3*4))
Which is exactly how they did it before we started using Brackets in Maths 😂 2+3x4=2+3+3+3+3=14, not complicated.
I mean, it is pretty clear here that you do not really understand the purpose of notation, nor what maths is. Notation is just a constructed language to convey a mathematical idea, it’s malleable
Really though, maths is so much more than “3+5=8 because that’s the correct answer!” But why is it the correct answer? In what context? What is the definition of addition? How can you prove that 1+1=2 from fundamental axioms? This is harder to answer than you might think.
Read the comments and you’ll find multiple people telling him he is wrong, with references 😂 His usual comeback is “well, that doesn’t prove that it’s taught everywhere”, yeah only that they ALL say the same thing! 😂 And he even admitted at one point he couldn’t find his rule in any Maths textbooks. 😂 I even tried to tell him myself, and he deleted my comment because I proved he was wrong 😂
Is well-known to be overridden with people who do not know how to do order of operations 😂 On Mastodon I’ve seen people asking where is a better place to take Maths problems
If you want a book about this
I have plenty of Maths textbooks, which for some reason you refuse to look in
“comprehensive handbook” - so, yet again, not a Maths textbook 🙄
“first published in 1945 in Russia” - the order of operations rules are older than 1945 😂
“frequently used guide for scientists, engineers, and technical university students” - notably no mention of Mathematicians
I’m sure you could also find stuff about this in a set theory book
and you could find this in a high school Maths textbook
Though good luck understanding them without sufficient experience in high-level maths
You know teachers here are required to have a Masters in Maths right?? 😂
But why is it the correct answer?
Count up and find out, or use some Cuisenaire rods. This is how young kids learn to do it
In what context?
The context of Addition 🙄
What is the definition of addition?
1+1=2, then inductively proven for all subsequent numbers
How can you prove that 1+1=2 from fundamental axioms?
It’s true by definition
This is harder to answer than you might think
Not hard at all. 1+1=2 by definition, then the rest of the numbers are proven inductively. You know there are several species of animals that also know how to count, right?
Social conventions are real, well defined things. Some mathematicians like to pretend they aren’t, while using a truckload of them; that’s a hypocritical opinion.
That’s not to say you can’t change them. But all of basic arithmetic is a social convention, you can redefine the numbers and operations any time you want too.
Save yourself the trouble - Smartman Apps is a crank. They categorically will not comprehend the difference between the notation we made up and how numbers work. Dingus keeps saying ‘animals can count’ like that proves parentheses-first is completely different! from distribution.
Why’d Russel and Whitehead bother with the Principia Mathematica when they could just point to Clever Hans?
Some people insist there’s no “correct” order for the basic arithmetic operations. And worse, some people insist the correct order is parenthesis first, then left to right.
Both of those sets of people are wrong.
And those people are wrong
As per Maths textbooks
All Maths textbooks are wrong?? 😂
Hopefully you can see where their confusion might come from, though. PEMDAS is more P-E-MD-AS. If you have a bunch of unparenthesized addition and subtraction, left to right is correct. A lot of like, firstgrader math problems are just basic problems that are usually left to right (but should have some extras to highlight PEMDAS somewhere I’d hope).
So they’re mostly telling you they only remember as much math as a small child that barely passed math exercizes.
You can do addition and subtraction in any order and it’s still correct
If you have a bunch of unparenthesized addition and subtraction, left to right doesn’t matter.
1 + 2 + 3 = 3 + 2 + 1
True, but as with many things, something has to be the rule for processing it. For many teachers as I’ve heard, order of appearance is ‘the rule’ when commutative properties apply. … at least until algebra demands simplification, but that’s a different topic.
That’s because students often make mistakes with signs when they do it in a different order, so we tell them to stick to left to right
Well the rule is: any order goes. Summation is commutative.
No, you completely misunderstood my point. My point is not to describe all valid interpretations of the commutative property, but the one most slow kids will hear.
OFC the actual rule is the order doesn’t matter, but kids that don’t pick up on the nuance of the commutative property will still remember, “order of appearance is fine”.
Yes thank you! If you have a sum it is really great to order it in a way that makes it better to ad in your head and i think that lots of people do that without thinking about it. X=2+3+1+6+2+4+7+5 X=2+3+5+4+6+7+1+2 X=5+5 + 10 +7+1+2 X=10 + 10 + 7+3 X=10 + 10 + 10
Right, because 1-2-3=3-2-1.
No, 1-2-3=-3-2+1. You changed the signs on the 1 and the 3.
You flipped the sign on the 3 and 1.
I did not flip any signs, merely reversed the order in which the operations are written out. If you read the right side from right to left, it has the same meaning as the left side from left to right.
Hell, the convention that the sign is on the left is also just a convention, as is the idea that the smallest digit is on the right (which should be a familiar issue to programmers, if you look up big endian vs little endian)
Yes you did! 😂
No, merely reversing the order gives -3-2+1 - you changed the signs on the 1 and 3.
Starts with -3, which you changed to +3
when you don’t change any of the signs it does 😂
Nope, it’s a rule of Maths, Left Associativity.
If that’s your idea of reversing the order, then you’re not talking about the same thing as [email protected]. They’re talking about the order of operations and the associativity/commutativity property. You’re talking about the order of the symbols.
PE(MD)(AS)
Now just remember to account for those parentheses first…
Those Brackets don’t matter. I don’t know why people insist it does
Huh I just remembered the orders of arithmetic but parentheses trump all so do them first (I use them in even the calculator app). Mean I assume that’s that that says but never learned that acronym is all. Now figuring out categories of words;really does my noodle in sometimes. Cause some words can be either depending on context. Math when it’s written out has (mostly) the same answer. I say mostly because somewhere in the back of my brain there are some scenarios where something more complicated than straight arithmetic can come out oddly but written as such should come out the same.
I mean, arithmetic order is just convention, not a mathematical truth. But that convention works in the way we know, yes, because that’s what’s… well… convention
Nope, rules arising from the definition of the operators in the first place.
It most certainly is a mathematical truth!
The mnemonics are conventions, the rules are rules
The rules are socially agreed upon. They are not a mathematical truth. There is nothing about the order of multiple different operators in the definition of the operators themselves. An operator is simply just a function or mapping, and you can order those however you like. All that matters is just what calculation it is that you’re after
Nope! Universal laws.
Yes they are! 😂
That’s exactly where it is. 2x3 is defined as 2+2+2, therefore if you don’t do Multiplication before Addition you get wrong answers
No you can’t! 😂 2+3x4=5x4=20, Oops! WRONG ANSWER 😂
And if you want the right answer then you have to obey the order of operations rules
That’s a very simplistic view of maths. It’s convention https://en.wikipedia.org/wiki/Order_of_operations
Just because a definition of an operator contains another operator, does not require that operator to take precedence. As you pointed out, 2+3*4 could just as well be calculated to 5*4 and thus 20. There’s no mathematical contradiction there. Nothing broke. You just get a different answer. This is all perfectly in line with how maths work.
You can think of operators as functions, in that case, you could rewrite 2+3*4 as add(2, mult(3, 4)), for typical convention. But it could just as well be mult(add(2, 3), 4), where addition takes precedence. Or, similarly, for 2*3+4, as add(mult(2, 3), 4) for typical convention, or mult(2, add(3, 4)), where addition takes precedence. And I hope you see how, in here, everything seems to work just fine, it just depends on how you rearrange things. This sort of functional breakdown of operators is much closer to mathematical reality, and our operators is just convention, to make it easier to read.
Something in between would be requiring parentheses around every operator, to enforce order. Such as (2+(3*4)) or ((2+3)*4)
The Distributive Law and Arithmetic is very simple.
Nope, a literal Law. See screenshot
Isn’t a Maths textbook, and has many mistakes in it
Yes it does 😂
2+3x4=2+3+3+3+3=14 by definition of Multiplication
2+3x4=5x4=20 Oops! WRONG ANSWER 😂
No, I pointed out that it can’t be calculated like that, you get a wrong answer, and you get a wrong answer because 3x4=3+3+3+3 by definition
Just a wrong answer and a right one. If I have 1 2 litre bottle of milk, and 4 3 litre bottles of milk, even young kids know how to count up how many litres I have. Go ahead and ask them what the correct answer is 🙄
You got a wrong answer when you broke the rules of Maths. Spoiler alert: I don’t have 20 litres of milk
A provably wrong answer 😂
2+3x4=20 is not in line with how Maths works. 2+3+3+3+3 does not equal 20 😂
rule
And it gives you a wrong answer 🙄 I still don’t have 20 litres of milk
No, I see quite clearly that I have 14 litres of milk, not 20 litres of milk. Even a young kid can count up and tell you that
Correctly or not
The notation is, the rules aren’t
No it wouldn’t. You know we’ve only been using brackets in Maths for 300 years, right? Order of operations is much older than that
Which is exactly how they did it before we started using Brackets in Maths 😂 2+3x4=2+3+3+3+3=14, not complicated.
I mean, it is pretty clear here that you do not really understand the purpose of notation, nor what maths is. Notation is just a constructed language to convey a mathematical idea, it’s malleable
And yeah, it’s easy to just say “this page is wrong!” without any further argument. Nothing you referenced proved the convention as law, and neither is there any mathematical basis for any proof, because it simply is nonsensical to “prove” a notation. Have another source for this being convention https://www.themathdoctors.org/order-of-operations-why/ or https://math.stackexchange.com/questions/884765/mathematical-proof-for-order-of-operations. If you want a book about this, then there’s https://en.wikipedia.org/wiki/Bronshtein_and_Semendyayev that is cited by wikipedia. I’m sure you could also find stuff about this in a set theory book. Though good luck understanding them without sufficient experience in high-level maths
Really though, maths is so much more than “3+5=8 because that’s the correct answer!” But why is it the correct answer? In what context? What is the definition of addition? How can you prove that 1+1=2 from fundamental axioms? This is harder to answer than you might think.
says person who doesn’t understand that there is only one possible answer to 2+3x4. Even kids who are still counting up know what it is
Yep, and the rules aren’t. 2+3x4 can only ever equal 14. In Germany it’s written 2+3.4, and it’s still equal to 14, because the rules are universal
says person ignoring the textbook screenshots explaining why it’s a Law 🙄
Yes there is. See textbook screenshots 🙄
It proves the rules 🙄
Read the comments and you’ll find multiple people telling him he is wrong, with references 😂 His usual comeback is “well, that doesn’t prove that it’s taught everywhere”, yeah only that they ALL say the same thing! 😂 And he even admitted at one point he couldn’t find his rule in any Maths textbooks. 😂 I even tried to tell him myself, and he deleted my comment because I proved he was wrong 😂
Is well-known to be overridden with people who do not know how to do order of operations 😂 On Mastodon I’ve seen people asking where is a better place to take Maths problems
I have plenty of Maths textbooks, which for some reason you refuse to look in
“comprehensive handbook” - so, yet again, not a Maths textbook 🙄
“first published in 1945 in Russia” - the order of operations rules are older than 1945 😂
“frequently used guide for scientists, engineers, and technical university students” - notably no mention of Mathematicians
and you could find this in a high school Maths textbook
You know teachers here are required to have a Masters in Maths right?? 😂
Count up and find out, or use some Cuisenaire rods. This is how young kids learn to do it
The context of Addition 🙄
1+1=2, then inductively proven for all subsequent numbers
It’s true by definition
Not hard at all. 1+1=2 by definition, then the rest of the numbers are proven inductively. You know there are several species of animals that also know how to count, right?
Social conventions are real, well defined things. Some mathematicians like to pretend they aren’t, while using a truckload of them; that’s a hypocritical opinion.
That’s not to say you can’t change them. But all of basic arithmetic is a social convention, you can redefine the numbers and operations any time you want too.
So are the laws of nature, that Maths arises from
No, you making false accusations against Mathematicians is a strawman
You can change the conventions, you cannot change the rules
Nope, law of nature. Even several animals know how to count.
And you end up back where you started, since you can’t change the laws of nature
Well, this is just a writing standard that is globally agreed on,
The writing rules are defined by humans not by natural force
(That one thing and another thing are two things, is a rule from nature, as comparison)
Save yourself the trouble - Smartman Apps is a crank. They categorically will not comprehend the difference between the notation we made up and how numbers work. Dingus keeps saying ‘animals can count’ like that proves parentheses-first is completely different! from distribution.
Why’d Russel and Whitehead bother with the Principia Mathematica when they could just point to Clever Hans?
No, it’s a universal rule of Maths
Maths is for describing natural forces, and is subject to those laws
Yep, there are even some animals who understand that, and all of Maths is based upon it.