854
6÷2(1+2) (programming.dev)
submitted 11 months ago* (last edited 11 months ago) by wischi@programming.dev to c/memes@lemmy.ml

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 :)

you are viewing a single comment's thread
view the rest of the comments
[-] DRx@lemmy.world 5 points 11 months ago* (last edited 11 months ago)

Def not a math major (BS/PharmD), but your explanation was like seeing through a visual illusion for the first time! lol

I was always taught PEMDAS growing up, and that the MD and the AS was read left to right in an equation like above. But stating the division as a fraction completely changes my mind now about how this calculation works. I think what would happen in a calculation I use every day if the former was used.

Example: Cockcroft-Gault Equation (estimation of renal function)

(140-age)(kg) / 72(SCr) vs (140-age) X kg ➗72 X SCr

In the first eq (correct one) an 80yo patient who weighs 65kg and has an SCr ~ 1.5 = 36.11

In the latter it = 81.25 (waaay too high for an 80yo lol)

edit: calculation variable

[-] SmartmanApps@programming.dev 1 points 8 months ago

But stating the division as a fraction completely changes my mind now about how this calculation works

But division and fraction aren't the same thing - the former separates terms, the latter is a single term.

(140-age)(kg) / 72(SCr) vs (140-age) X kg ➗72 X SCr

The different answers for these two isn't because of / vs ➗, but because in the second one you have added extra multiplications in, thus breaking up some of the terms, and SCr has consequently been flipped from being in the denominator to being in the numerator. i.e. AK/72Scr vs. AK/72xSCr.

this post was submitted on 12 Dec 2023
854 points (96.4% liked)

Memes

45646 readers
1180 users here now

Rules:

  1. Be civil and nice.
  2. Try not to excessively repost, as a rule of thumb, wait at least 2 months to do it if you have to.

founded 5 years ago
MODERATORS