• Tlaloc_Temporal@lemmy.ca
      link
      fedilink
      English
      arrow-up
      1
      arrow-down
      1
      ·
      6 months ago

      I never commented on the convenience or usefulness of any method, just tried to explain why so many people get stuck on 0.999… = 1 and are so recalcitrant about it.

      If you can accept that 1/3 is 0.333… then you can multiply both sides by three and accept that 1 is 0.99999…

      This is a workaround of the decimal flaw using algebraic logic. Trying to hold both systems as fully correct leads to a conflic, and reiterating the algebraic logic (or any other proof) is just restating the problem.

      The problem goes away easily once we understand the limits of the decimal system, but we need to state that the system is limited! Otherwise we get conflicting answers and nothing makes sense.

        • Tlaloc_Temporal@lemmy.ca
          link
          fedilink
          English
          arrow-up
          1
          arrow-down
          1
          ·
          6 months ago

          Decimals work fine to represent numbers, it’s the decimal system of computing numbers that is flawed. The “carry the 1” system if you prefer. It’s how we’re taught to add/subtract/multiply/divide numbers first, before we learn algebra and limits.

          This is the flawed system, there is no method by which 0.999… can become 1 in here. All the logic for that is algebraic or better.

          My issue isn’t with 0.999… = 1, nor is it with the inelegance of having multiple represetations of some numbers. My issue lies entirely with people who use algebraic or better logic to fight an elementary arithmetic issue.

          People are using the systems they were taught, and those systems are giving an incorrect answer. Instead of telling those people they’re wrong, focus on the flaws of the tools they’re using.

            • Tlaloc_Temporal@lemmy.ca
              link
              fedilink
              English
              arrow-up
              1
              arrow-down
              1
              ·
              edit-2
              6 months ago

              I don’t really care how many representations a number has, so long as those representations make sense. 2 = 02 = 2.0 = 1+1 = -1+3 = 8/4 = 2x/x. That’s all fine, we can use the basic rules of decimal notation to understand the first three, basic arithmetic to understand the next three, and basic algebra for the last one.

              0.999… = 1 requires more advanced algebra in a pointed argument, or limits and infinite series to resolve, as well as disagreeing with the result of basic decimal notation. It’s steeped in misdirection and illusion like a magic trick or a phishing email.

              I’m not blaming mathematicians for this, I am blaming teachers (and popular culture) for teaching that tools are inflexible, instead of the limits of those systems.

              In this whole thread, I have never disagreed with the math, only it’s systematic perception, yet I have several people auguing about the math with me. It’s as if all math must be regarded as infinitely perfect, and any unbelievers must be cast out to the pyre of harsh correction. It’s the dogmatic rejection I take issue with.

                • Tlaloc_Temporal@lemmy.ca
                  link
                  fedilink
                  English
                  arrow-up
                  1
                  arrow-down
                  1
                  ·
                  6 months ago

                  Again, I don’t disagree with the math. This has never been about the math. I get that ever model is wrong, but some are useful. Math isn’t taught like that though, and that’s why people get hung up things like this.

                  Basic decimal notation doesn’t work well with some things, and insinuates incorrect answers. People use the tools they were taught to use. People get told they’re doing it wrong. People give up on math, stop trying to learn, and just go with what they can understand.

                  If instead we focus on the limitations of some tools and stop hammering people’s faces in with bigger equations and dogma, the world might have more capable people willing to learn.

          • those systems are giving an incorrect answer

            When there’s an incorrect answer it’s because the user has made a mistake.

            Instead of telling those people they’re wrong

            They were wrong, and I told them where they went wrong (did something to one side of the equation and not the other).

            • Tlaloc_Temporal@lemmy.ca
              link
              fedilink
              English
              arrow-up
              1
              arrow-down
              2
              ·
              6 months ago

              The system I’m talking about is elementary decimal notation and basic arithmetic. Carry the 1 and all that. Equations and algebra are more advanced and not taught yet.

              There is no method by which basic arithmetic and decimal notation can turn 0.999… into 1. All of the carry methods require starting at the smallest digit, and repeating decimals have no smallest digit.

              If someone uses these systems as they were taught, they will get told they’re wrong for doing so. If we focus on that person being wrong, then they’re more likely to give up on math entirely, because they’re wrong for doing as they were taught. If we focus on the limitstions of that system, then they have the explanation for the error, and an understanding of why the more complicated system is preferable.

              All models are wrong, but some are useful.

              • not taught yet

                What do you mean not taught yet? There’s nothing in the meme to indicate this is a primary school problem. In fact it explicitly has a picture of an adult, so high school Maths is absolutely on the table.

                There is no method by which basic arithmetic and decimal notation can turn 0.999… into 1.

                In high school we teach that they are the same thing. i.e. limits of accuracy, 1 isn’t the same thing as 1.000…, but rather 1+/- some limit of accuracy (usually 1/2). Of course in programming it matters if you’re talking about an integer 1 or a floating point 1.

                If someone uses these systems as they were taught, they will get told they’re wrong for doing so

                The only people I’ve seen get things wrong is people not using the systems correctly (such as the alleged “proof” in this thread, which broke several rules of Maths and as such didn’t prove anything), and it’s a teacher’s job to point out how to use them correctly.

                • Tlaloc_Temporal@lemmy.ca
                  link
                  fedilink
                  English
                  arrow-up
                  1
                  arrow-down
                  2
                  ·
                  6 months ago

                  What do you mean not taught yet?

                  I mean those more advanced methods are taught after basic arithmetic. There are plenty of adults that operate primarily with 5th grade math, and a scary number of them do finances…

                  limits of accuracy

                  This isn’t about limits of accuracy, we’re working with abstract values and ideal systems. Any inaccuracies must be introduced by those systems.

                  If you think the system isn’t at fault here, please show me how basic arithmetic can make 0.999… into 1. Show me how the carry method deals with Infinity correctly. If every error is just using the system incorrectly, then a correct use of the system must be applicable to everything, right? You shouldn’t need a new system like algebra to be correct, right?

                  • This isn’t about limits of accuracy

                    According to who? Where does it say what it’s about? It doesn’t.

                    please show me how basic arithmetic can make 0.999

                    You still haven’t shown why you’re limiting yourself to basic arithmetic. There isn’t anything at all in the meme to indicate it’s about basic arithmetic only. It’s just some Maths statements with no context given.

                    then a correct use of the system must be applicable to everything, right?

                    Different systems for different applications. Sometimes multiple systems for one problem (e.g. proofs).

                    You shouldn’t need a new system like algebra to be correct, right?

                    Limits of accuracy isn’t algebra.