188
SBA #119 maths
(lemmy.nz)
If I need to use anything other than p you need to rewrite the expression
BODMAS
- Brackets
- Of
- Division
- Multiplication
- Addition
- Subtraction
Let me just, ahem
1-2+3/(3+3)×2+3×6/3 = 1-2+3/(3+3)×2+1×6 = 1-2+3/(3+3)×2+6 = 7-2+3/(3+3)×2 = 7-2+3/(6+6) = 7-2+(1/2+1/2) = 5+(1/2+1/2) = 5+1=6
Ahh, yes, DMAMDSBA :P
Let's just say BODMAS/PEMDAS isn't all end-all be-all. They're good, but there's also better
For those interested, see: basic number properties
Idk what basic number properties are, but isn't GEMS the new best/simple standard?
Not really.
Math, at it's basis, doesn't have an order of operation, as I've illustrated in my previous comment by breaking the left-to-right rule, doing addition before multiplication and ignoring brackets until the very end.
It only exists as a method of teaching students because it works. It's simple and easy to remember.
The rest is me explaining how basic properties work:
Instead, mathematicians have long derived the basic properties that are supposed to be taught to students later on and is pretty much the first thing you learn in mathematical analysis in uni.
Those are:
- commutative: a+b=b+a | same for mult
- associative: (a+b)+c=a+(b+c) | same for mult
- distributive: a×(b+c)=a×b+a×c
- identity: a+0=a | a×1=a
- inversion: a+(-a)=0 | a×(1/a)=1
This is what math is. Every equation is solved using those properties. Every theorem can be broken down into those actions. (Technically speaking, you can break it down even more - into addition only)
This is why in GEMA, BODMAS, etc, you have multiplication and division before addition and subtraction. Because (a×b)+c=a×(b+c) isn't a property that exists. Try it. The sides won't always be equal.
And those properties are also the reason why you don't have to abide by an order of operations. Commutative and associative properties directly contradict them without making the solutions incorrect.
My uni math was more extensive than expected(read 'practically useless' but also occasionally fun) and no two math profs simplify in any relatively similar style whatsoever(This was beyond a headache before wolframAlpha). My personal experiences demand I still strongly lean toward any universally agreed upon convention. Don't you think with how opinionated and picky mathematicians are, it's still better to keep to a language everyone can participate in? It just seems almost conflicting with the spirit of math to not somewhat favor a most direct base or foundation if only for convenience. I suppose you could argue we DO have wolframAlpha, so who cares, and I guess I just feel it's important that math stay teachable via human to human interaction and so any of the Acronyms seem much more helpful than not
Well, in my case, the order of operation in uni wasn't brought up even once. But it was also a prestigious one with notoriously challenging math courses, so I may be a little out of touch in that regard. (Let me brag, ok?)
No, I do not think those conventions are needed. Because they aren't fundamental. You don't really know math until you understand how PEMDAS or w/e came to be and why it is the way that it is.
Not following those conventions doesn't automatically make your solution incorrect. That's the most important thing.
It shouldn't matter how you solve as long as it is a correct solution.
There may, indeed, be inconsistencies in how things are written out. Whether 2x is the same as 2×x, for example. It's common practice that it isn't, but it's also often not important.
If you write out the solution, people will understand what you mean by simply following it.
Compare:
6÷(2+4) = 6÷2(1+2) = 6÷2÷3 = 1
And
6÷(6÷3×(1+2)) = 6÷2(1+2) = 6÷2×3 = 9
They are written in the same manner, but those are 2 different equations to begin with, with their respective correct solution. For the same reason why 2x and 2×x may be the same or not. (Replace 1+2 with x, you'll get 6/2x vs. 6x/2)
It's not a matter of order of operations, but a matter of context. Whether juxtaposition took place or not. In real research, 2x always has a context.
Besides, the equations aren't usually written out that way, aren't they? You would do this (except for the dot in multiplication, unless it's needed)
I'm still not getting your side of all of this. Are you basically saying that the order of operations should be reduced to two rules:
- Multiplication is stronger than Addition. (When they fight, Multiplication wins).
- Grouping Symbols override everything. (Parentheses/Brackets/Fractions are the "bosses" that force you to do things out of order).
Or are you saying we don't need order of operations at all?
I'm saying it's not needed at all.
It's good for teaching kids quickly, but it's not a real rule you have to follow.
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(2 replies)
USE GEMS USE GEMS!
It's...a shitpost because Patrick and you are wrong?
I guess the joke is that it wasn't an ambiguous expression in the first place and that pedmas/bedmas wasn't the issue, or rather using just it here is the problem?
When you have multiplication expressed as numbers joined without a symbol, that takes precedence at the current layer, where layers are created using brackets, fraction symbols, superscript exponents and concatenated multiplies.
I'm not sure this resolves all ambiguity, but it simplifies the rule to just doing multiplication/division before addition/subtraction. It seems simple enough in my mind, so I'd need to see a counter example if it does break down.
Though I hate how mainstream math problems/puzzles always end up being an order of operations problem, which I'd argue isn't even math but more of a metamath thing. If you're using math to solve a real problem, the correct order of operations will be determined by logic, not any conventions.
Like if it takes you 5 seconds to get in your car and 12 seconds per km traveled, and 5 seconds to get out of your car, if you multiply the 10 seconds to get in or out by the distance, you'll have a wrong answer. It'll always be distance traveled in km times 12 seconds/km plus the 10 seconds, and the math works on the units as well as the numbers to show you did it in a way that makes sense.
The real answer is "what's the fucking context for how these numbers are being used?"
If it's "just as written on a test" I think asking for clarification on order would be accepted.
If it's an actual context of some kind then that alone dictactes the way you solve it.
Can't quickly come up with a word problem for this one though.
this post was submitted on 13 May 2026
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