• PeriodicallyPedantic@lemmy.ca
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    19 days ago

    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 PEDMAS is a very strict order. Other places say that it is PE 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.

    • different places teach different conventions

      But they all teach the same rules

      some places say that PEDMAS is a very strict order

      Which is totally fine and works

      Other places say that it is PE D|M A|S,

      Which is also totally fine and works

      even in this post, say it’s PEMDAS

      Also totally fine and works

      it’s simply a matter of if the people talking agree on the convention to use

      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

      can’t agree on

      Educated people agree that which convention you use doesn’t matter.

      • PeriodicallyPedantic@lemmy.ca
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        12 days ago

        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.

        • That’s not true

          Yes it is

          PEDMAS: 8÷2x4 = 4x4 = 16

          Yep.

          PEMDAS: 8÷2x4 = 8÷8 = 1

          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

          PE M|D A|S: 8÷2x4 = 4x4 = 16

          Yep, same answer regardless of the order 🙄

          And thats not even getting into juxtaposition operations,

          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.

          where fields like physics use conventions that differ from most other field

          Nope! The obey all the rules of Maths. They would get wrong answers if they didn’t

          you’re missing the point

          No, you are…

          It could be SAMDEP and math would still work

          No it can’t because no it wouldn’t 😂

          you’d just rearrange the equation.

          Says someone who didn’t rearrange “PEMDAS: 8÷2x4 = 8÷8 = 1” and got the wrong answer 😂

          The rules don’t change

          Hence why “PEMDAS: 8÷2x4 = 8÷8 = 1” was wrong. You violated the rule of Left Associativity

          • PeriodicallyPedantic@lemmy.ca
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            12 days ago

            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?

            Says someone who didn’t rearrange "PEMDAS

            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.

            No it can’t because no it wouldn’t 😂

            All conventions can produce the correct answer, when appropriately arranged for that convention, because the conventions are not laws of mathematics, they are conventions.

            Nope! The obey all the rules of Maths. They would get wrong answers if they didn’t

            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

            • Ok, then explain prefix and postfix, where these conventions don’t apply

              The conventions don’t apply, the rules still apply. Maths notation and the rules of Maths aren’t the same thing.

              How can these be rules of math when they didn’t universally apply?

              The rules do universally apply 🙄

              The order of operations tells us how to interpret an equation without rearranging it

              Yep, and you showed you don’t know the rules 🙄

              When you pick a different convention, you need to rearrange it to get the same answer

              Not necessarily, though it makes it easier (but also leads a lot of people to make mistakes with signs, as you found out 😂 )

              What you did was rearrange the equation

              To show you how to correctly do “Multiplication first”. 🙄

              which you can only do if you are already following a specific convention

              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.

              because the conventions are not laws of mathematics, they are conventions

              And putting the Multiplication inside Brackets isn’t a convention anywhere 🙄

              They obey the laws of math. Conventions aren’t laws of math, they’re conventions

              Yep, and you ignored both, hence your wrong answer 🙄

              And a quick Google search will tell you that not everyone puts juxtaposition at a higher precedent than multiplication

              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 🙄

              it’s a convention

              No it isn’t. It’s against the rules. 🙄 Again, you won’t find this alleged “convention” in any Maths textbook

              As long as people are using the same convention, they’ll agree on an answer and that answer is correct

              Unless they disobeyed the rules, in which case they are all wrong 🙄

              You can be mean all you like, that doesn’t change the nature of conventions

              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 🙄

              • PeriodicallyPedantic@lemmy.ca
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                2 days ago

                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.

                • Yeah, you clearly don’t even know what a convention is, and what are math conventions and math “rules” as you put it

                  Says person who actually doesn’t know the difference, as per Maths textbooks

                  You’re wrong

                  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 would show you that and explain why

                  Even a 2 minute Google search will bring up Maths textbooks which prove that Google is wrong 🙄

                  I’m done being Google for you

                  Maths teachers don’t use Google - that’s what Maths textbooks are for

                  when you’re not willing to Google it yourself

                  says person who was unwilling to use Google to find Maths textbooks 🙄

                  • PeriodicallyPedantic@lemmy.ca
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                    47 minutes ago

                    Wikipedia

                    In mathematics and computer programming, the order of operations is a collection of conventions about which arithmetic operations to perform first in order to evaluate a given mathematical expression

                    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?