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 :)

  • kuneho@lemmy.world
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    1 year ago

    isn’t that division sign I only saw Americans use written like this (÷) means it’s a fraction? so it’s 6÷2, since the divisor (or what is it called in english, the bottom half of the fraction) isn’t in parenthesis, so it would be foolish to put the whole 2(1+2) down there, there’s no reason for that.

    so it’s (6/2)*(1+2) which is 3*3 = 9.

    the other way around would be 6÷(2(1+2)) if the whole expression is in the divisor and than that’s 1.

    tho I’m not really proficient in math, I have eventually failed it in university, but if I remember my teachers correctly, this should be the way. but again, where I live, we never use the ÷ sign, only in elementary school where we divide on paper. instead we use the fraction form, and with that, these kind of seemingly ambiguous expressions doesn’t exist.

    • Ultraviolet@lemmy.world
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      1 year ago

      The ÷ sign isn’t used by “Americans”, it’s used by small children. As soon as you learn basic mathematical notation in your introductory algebra class, you’ve outgrown the use of that symbol.

      • Lazhward@lemmy.world
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        1 year ago

        Children here in the Netherlands use : as a divisor symbol. I don’t know whether the ÷ sign is particularly American, but it’s not universal.

    • Spacehooks@reddthat.com
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      1 year ago

      It seems Americans are taught pemdas and not bodas.

      I Looked up doing factorials and n! = n(n – 1) is used interchangeably with n! = n*(n – 1)

      So Americans will multiply anything first. This is why I put 6 ÷ ( n*(n – 1)) in excel to avoid confusion.

      • kuneho@lemmy.world
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        1 year ago

        I Looked up doing factorials and n! = n(n – 1) is used interchangeably with n! = n*(n – 1)

        yeah, the way I have been taught is that either you put the multiplication sign there or not, it’s the exact same, there’s absolutely no difference in n(n-1) and n*(n-1). in the end, you treat it like the * sign is there and it’s just matter of convenience you can leave it off.

      • Echrichor@feddit.uk
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        1 year ago

        Americans use PEMDAS, in the UK we use BODMAS, and I assume other English speaking countries use one or the other, but there is no difference between them in terms of order of operations, because it’s:

        1. brackets (parenthesis)

        2. orders (exponentials)

        3. division & multiplication (multiplication & division), performed left to right

        4. addition & subtraction, performed left to right

        People who choose to divide or multiply first because of the acronym have just forgotten that they go together left to right.

        • Spacehooks@reddthat.com
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          1 year ago

          “Next, we perform operations on multiplication or division from left to right.” Found that in like 20 sources. Funny how I didn’t see any of that yesterday.

          This is crazy swear never heard that rule.

          100% sure I solved everything in class following the acronym. Glad we sorted this out before I helped any kids do Homework.