https://zeta.one/viral-math/

I wrote a (very long) blog post about those viral math problems and am looking for feedback, especially from people who are not convinced that the problem is ambiguous.

It’s about a 30min read so thank you in advance if you really take the time to read it, but I think it’s worth it if you joined such discussions in the past, but I’m probably biased because I wrote it :)

  • dgmib@lemmy.world
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    7 months ago

    You state that the ambiguity comes from the implicit multiplication and not the use of the obelus.

    I.e. That 6 ÷ 2 x 3 is not ambiguous

    What is your source for your statement that there is an accepted convention for the priority of the iinline obelus or solidus symbol?

    As far as I’m aware, every style guide states that a fraction bar (preferably) or parentheses should be used to resolve the ambiguity when there are additional operators to the right of a solidus, and that an obelus should never be used.

    Which therefore would make it the division expressed with an obelus that creates the ambiguity, and not the implicit multiplication.

    (Rest of the post is great)

    • wischi@programming.devOP
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      7 months ago

      In this case it’s actually the absence of sources. I couldn’t find a single credible source that states that ÷ has somehow a different operator priority than / or that :

      The only things there are a lot of are social media comments claiming that without any source.

      My guess is that this comes from a misunderstanding that the obelus sign is forbidden in a lot of standards. But that’s because it can be confused with other symbols and operations and not because the order of operations is somehow unclear.

      • dgmib@lemmy.world
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        7 months ago

        What is your source for the priority of the / operator?

        i.e. why do you say 6 / 2 * 3 is unambiguous?

        Every source I’ve seen states that multiplication and division are equal priority operations. And one should clarify, either with a fraction bar (preferably) or parentheses if the order would make a difference.

        • wischi@programming.devOP
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          7 months ago

          Same priority operations are solved from left to right. There is not a single credible calculator that would evaluate “6 / 2 * 3” to anything else but 9.

          But I challenge you to show me a calculator that says otherwise. In the blog are about 2 or 3 dozend calculators referenced by name all of them say the same thing. Instead of a calculator you can also name a single expert in the field who would say that 6 / 2 * 3 is anything but 9.

          • dgmib@lemmy.world
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            7 months ago

            Will you accept wolfram alpha as credible source?

            https://mathworld.wolfram.com/Solidus.html

            Special care is needed when interpreting the meaning of a solidus in in-line math because of the notational ambiguity in expressions such as a/bc. Whereas in many textbooks, “a/bc” is intended to denote a/(bc), taken literally or evaluated in a symbolic mathematics languages such as the Wolfram Language, it means (a/b)×c. For clarity, parentheses should therefore always be used when delineating compound denominators.

            • Danksy@lemmy.world
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              7 months ago

              The link references “a/bc” not “a/b*c”. The first is ambiguous, the second is not.