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 :)

  • Spacehooks@reddthat.com
    link
    fedilink
    English
    arrow-up
    3
    arrow-down
    3
    ·
    11 months 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
      link
      fedilink
      arrow-up
      4
      arrow-down
      1
      ·
      edit-2
      11 months 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.

      • Spacehooks@reddthat.com
        link
        fedilink
        English
        arrow-up
        1
        ·
        11 months 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.

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

      Yeah, there’s a problem with some lazy textbook authors, which I talked about here. A term is defined as ab=(axb), and yet many textbooks lazily write it as ab=axb, which is fine if that’s the whole expression, but NOT fine if the expression is a/bc (a/(bxc) and a/bxc AREN’T the same thing!), and so we end up with people removing brackets prematurely and getting wrong answers. In other words, in your case, only n!=n(n – 1) and n!=(nx(n – 1)) can be used interchangeably.