539
Whats your such opinion
(discuss.tchncs.de)
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
this post was submitted on 07 Dec 2023
539 points (87.7% liked)
Asklemmy
43945 readers
535 users here now
A loosely moderated place to ask open-ended questions
If your post meets the following criteria, it's welcome here!
- Open-ended question
- Not offensive: at this point, we do not have the bandwidth to moderate overtly political discussions. Assume best intent and be excellent to each other.
- Not regarding using or support for Lemmy: context, see the list of support communities and tools for finding communities below
- Not ad nauseam inducing: please make sure it is a question that would be new to most members
- An actual topic of discussion
Looking for support?
Looking for a community?
- Lemmyverse: community search
- sub.rehab: maps old subreddits to fediverse options, marks official as such
- !lemmy411@lemmy.ca: a community for finding communities
~Icon~ ~by~ ~@Double_A@discuss.tchncs.de~
founded 5 years ago
MODERATORS
Back in gradeschool I was always taught that in Pemdas, the parenthesis are assumed to be there in 8÷(2×(2+2)) where as 8÷2×(2+2) would be 16, 8÷2(2+2) is the above and equals 1.
Not quite. It's true you resolve what's inside the parentheses first, giving you. 8÷2(4) or 8÷2x4.
Now this is what gets most people. Even though Multiplication technically comes before Division the Acronym PEMDAS, that's really just to make it sound correct phonetically. Really they have equal priority in the order of operations and the appropriate way to resolve the problem is to work from left to right solving each multiplication or division sign as you encounter them. Giving you 16. Same for addition and subtraction.
So basically the true order of operations is:
Source: Mechanical Engineering degree so an unfortunate amount of my life spent in math and physics classes.
Absolutely, its all seen as equal so it has to go left to right However as I said in the beginning the way I was taught atleast, is when you see 2(2+2) and not 2×(2+2) you assume that 2(2+2) actually means (2×(2+2 )) and so must do it together.
Ah sorry just realized what you were saying. I've never been taught that. Maybe it's just a difference in teaching styles, but it shouldn't be since it can actually change the outcome. The way I was always taught was if you see a number butted up against an expression in parentheses you assume there is a multiplication symbol there.
So you were taught that 2(2+2) == (2(2+2))
I was taught 2(2+2)==2*(2+2)
Interesting difference though because again, assuming invisible parentheses can really change up how a problem is done.
Edit: looks like theshatterstone54's comment assumed a multiplication symbol as well.
No, it means it's a Term (product). If a=2 and b=3, then axb=2x3, but ab=6.
2(2+2)==(2*(2+2)). More precisely, The Distributive Law says that 2(2+2)=(2x2+2x2).
That's basically what I was taught, too.
Edit to add: Ha, I just realized how similar our usernames are. Neat! :)
Basically the normal arithmetic operators are all left-associative which means if you have more than one you solve them left to right.
Not "inside parenthesis" (Primary School, when there's no coefficient), "solve parentheses" (High School, The Distributive Law). Also 8÷2(4)=8÷(2x4) - prematurely removing brackets is how a lot of people end up with the wrong answer (you can't remove brackets unless there is only 1 term left inside).
Yes, it's The Distributive Law.