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
    1
    ·
    8 months ago

    Well I’m not seeing the difference here. Yn+y= yn+y = y(n+1) = y × (n +1) I think we agree with that.

    • 💡𝚂𝗆𝖺𝗋𝗍𝗆𝖺𝗇 𝙰𝗉𝗉𝗌📱@programming.dev
      link
      fedilink
      English
      arrow-up
      1
      arrow-down
      2
      ·
      edit-2
      8 months ago

      Ok, that’s a start. In your simple example they are all equal, but they aren’t all the same.

      yn+y - 2 terms

      y(n+1) - 1 term

      y×(n +1) - 2 terms

      To see the difference, now precede it with a division, like in the original question…

      1÷yn+y=(1/yn)+y

      1÷y(n+1)=1/(yn+y)

      1÷y×(n +1)=(n +1)/y

      Note that in the last one, compared to the second one, the (n+1) is now in the numerator instead of in the denominator. Welcome to why having the (2+2) in the numerator gives the wrong answer.

      • Spacehooks@reddthat.com
        link
        fedilink
        English
        arrow-up
        2
        ·
        8 months ago

        Good example wish we had better math format.
        The granger issue is I thought multiple always happens first. But apparently it’s what’s left side first.

        • multiple always happens first. But apparently it’s what’s left side first

          Multiplication and division are equal precedence (and done left to right) if that’s what you’re talking about, but the issue is that a(b+c) isn’t “multiplication” at all, it’s a bracketed term with a coefficient which is therefore subject to The Distributive Law, and is solved as part of solving Brackets, which is always first. Multiplication refers literally to multiplication signs, of which there are none in the original question. A Term is a product, which is the result of a multiplication, not something which is to be multiplied.

          If a=2 and b=3, then…

          axb=2x3 - 2 terms

          ab=6 - 1 term

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

            That is what I am talking about. I would have got 1 by doing 2(2+2) = 8 first. Not because of bracket but because of “implied multiplication.”

            What I am learning here: 8÷2(2+2) is not same as 8÷2×(2+2)

            For several reasons:

            1. number next bracket is not the same as normal multiplication in rule book
            2. ÷ & × have right of way rule with whoever is left most wins.