11
submitted 2 months ago by Obelix@feddit.org to c/technology@lemmy.world
you are viewing a single comment's thread
view the rest of the comments
[-] barsoap@lemm.ee -2 points 2 months ago* (last edited 2 months ago)

It’s ambiguous which one of these is correct. Hence the best method we have for “correct” is left to right.

The solution accepted anywhere but in the US school system range from "Bloody use parenthesis, then" over "Why is there more than one division in this formula why didn't you re-arrange everything to be less confusing" to "50 Hertz, in base units, are 50s^-1^".

More practically speaking: Ultimately, you'll want to do algebra with these things. If you rely on "left to right" type of precedence rules re-arranging formulas becomes way harder because now you have to contend with that kind of implicit constraint. It makes everything harder for no reason whatsoever so no actual mathematician, or other people using maths in earnest, use that kind of notation.

[-] SmartmanApps@programming.dev 1 points 1 month ago* (last edited 1 month ago)

The solution accepted anywhere but in the US school system range from “Bloody use parenthesis, then” over “Why is there more than one division in this formula why didn’t you re-arrange everything to be less confusing” to “50 Hertz, in base units, are 50s-1”.

No, the solution is learn the rules of Maths. You can find them in Maths textbooks, even in U.S. Maths textbooks.

so no actual mathematician, or other people using maths in earnest, use that kind of notation.

Yes we do, and it's what we teach students to do.

[-] HereIAm@lemmy.world 1 points 2 months ago

I fully agree that if it comes down to "left to right" the problem really needs to be rewritten to be more clear. But I've just shown why that "rule" is a common part of these meme problems because it is so weird and quite esoteric.

[-] SmartmanApps@programming.dev 1 points 3 weeks ago

I fully agree that if it comes down to “left to right”

It never does

But I’ve just shown why that “rule” is a common part

No you didn't. You showed you didn't understand the rules. Doing addition first for 10-1+1 is 10+1-1, not 10-(1+1). It literally means add all positive numbers together first, which are +10 and +1, as per Maths textbooks...

Note in the above simplification of the coefficients we have 6-11+5-7+2=6+5+2-11-7=13-18=-5, and not, as you claim 6-(11+5)-(7+2)=6-16-9=-19

because it is so weird and quite esoteric

It's a convention, not a rule, and as such can be completely ignored by those who understand the rules. See literal textbook example

this post was submitted on 31 May 2025
11 points (92.3% liked)

Technology

73731 readers
1330 users here now

This is a most excellent place for technology news and articles.


Our Rules


  1. Follow the lemmy.world rules.
  2. Only tech related news or articles.
  3. Be excellent to each other!
  4. Mod approved content bots can post up to 10 articles per day.
  5. Threads asking for personal tech support may be deleted.
  6. Politics threads may be removed.
  7. No memes allowed as posts, OK to post as comments.
  8. Only approved bots from the list below, this includes using AI responses and summaries. To ask if your bot can be added please contact a mod.
  9. Check for duplicates before posting, duplicates may be removed
  10. Accounts 7 days and younger will have their posts automatically removed.

Approved Bots


founded 2 years ago
MODERATORS