🧵 Which way, math man?
Anonymous at Thu, 23 May 2024 00:35:13 UTC No. 16188757
Anonymous at Thu, 23 May 2024 01:12:41 UTC No. 16188801
>>16188757
another reason to use reverse polish notation
Anonymous at Thu, 23 May 2024 01:16:13 UTC No. 16188804
>>16188757
Already solved
Anonymous at Thu, 23 May 2024 01:43:44 UTC No. 16188821
>>16188801
You can malform equations with any notation
Anonymous at Thu, 23 May 2024 02:14:45 UTC No. 16188853
>>16188821
but at least with RPN there is no ambiguity, with infix notation there are at least two kinds of multiplying and dividing. 6*2(2+1) problem is based on the fact that in regular problem solving you rarely see parentheses multiplication with inline (rather than \frac{a}{b}) style division. Makes normies shit themselves with PEMDAS, while the only true answear is that no one would write it like that on paper, and on calculators you should use RPN to avoid the problems of trying to fit 2D pen&paper expressions onto 1D line of text
Anonymous at Thu, 23 May 2024 03:38:24 UTC No. 16188926
>>16188757
6÷2(1+2)
6/2*(1+2)
6/2*3
3*3
9
Anonymous at Thu, 23 May 2024 03:44:54 UTC No. 16188935
>>16188757
>Parentheses
>Exponents
>Multiplication and Division from left to right
>Addition and Subtraction from left to right
The correct answer is:
6/2(2+1)
6/2(3)
3(3)
9
Why are people so bad at understanding this? PEMDAS doesn't mean you always do multiplication before division or always do addition before subtraction, each of them are paired together and done from left to right after all the parentheses and exponents are resolved.
Anonymous at Thu, 23 May 2024 03:56:00 UTC No. 16188941
>>16188935
6 / (2+4) = 1
6 / (2+4) = 6 / 2(1+2)
Therefore
6 / 2(1+2) = 1
Get fucking shit on!
Anonymous at Thu, 23 May 2024 12:18:03 UTC No. 16189414
>>16188941
2 + 2 = 4
2 + 2 = 1 + 1
Therefore
1 + 1 = 4
2 = 4
My proof is infallible.
Anonymous at Thu, 23 May 2024 13:43:10 UTC No. 16189514
>>16188757
Stop using ÷ like a child
[math]\frac{6}{2(2+1)}=1[/math]
[math]\frac{6}{2}(2+1)=9[/math]
Anonymous at Thu, 23 May 2024 13:49:08 UTC No. 16189522
>>16189514
If you put 6 over 2(2+1) doesn't that mean you should fully solve 2(2+1) before dividing? You have to solve the top and bottom completely before dividing, you can't just pull part of the expression out as it suits you.
Anonymous at Thu, 23 May 2024 13:59:11 UTC No. 16189532
>>16188935
You live in age where 9% of all Americans think the Earth is flat, 18% cant find their own country on a world map, 38% believe in Creationism, and you wonder why they are bad at understanding PEMDAS?
Anonymous at Thu, 23 May 2024 14:15:44 UTC No. 16189547
The notation implies that 2(1+2) is grouped together as a single unit i.e., there is an implicit pair of parentheses surrounding it, hence, should be evaluated first thereby giving the answer 1.
Anonymous at Thu, 23 May 2024 14:20:07 UTC No. 16189552
>>16188757
1D math notation is the problem here. CStards still can't into 2D notation.
Anonymous at Thu, 23 May 2024 15:14:41 UTC No. 16189629
>>16188757
I thought this thread was about using a dedicated calculator or a phone and now I feel stupid.
Anonymous at Thu, 23 May 2024 15:17:13 UTC No. 16189632
>>16188941
>6 / (2+4) = 6 / 2(1+2)
But that's incorrect, you retard.
These are not equivalent expressions.
Anonymous at Thu, 23 May 2024 18:13:29 UTC No. 16189828
>>16189522
He didn't. He showed that the ÷ is ambiguous.
Anonymous at Thu, 23 May 2024 18:19:02 UTC No. 16189835
>>16189828
Oh, now I feel very stupid.
Anonymous at Fri, 24 May 2024 00:33:50 UTC No. 16190455
>>16188935
>6/2(3)
>3(3)
so why did you do the division before the parentheses? can't you follow PEMDAS
inb4 dats multiplication tho
no it's not where's the multiplication sign? 2(3) is parentheses multiplication
Anonymous at Fri, 24 May 2024 00:37:24 UTC No. 16190458
>>16190455
The "Parentheses" part of PEMDAS refers to solving all expressions INSIDE parentheses, not just anything INVOLVING parentheses.
>inb4 dats multiplication tho
That's literally the answer, yes. It's multiplication, not an expression within parentheses.
Anonymous at Fri, 24 May 2024 00:39:02 UTC No. 16190461
>>16190458
>The "Parentheses" part of PEMDAS refers to solving all expressions INSIDE parentheses, not just anything INVOLVING parentheses.
No you are completely fucking wrong. You solve everything involving parentheses first you brainlet. That's why there is the distinction
Anonymous at Fri, 24 May 2024 01:19:42 UTC No. 16190509
>>16190461
Care to back that up with a source?
Here's one that agrees with me: https://blog.prepscholar.com/pemdas
Pic related. Note how in the second step with 4(2)^2 they solve (2)^2 before 4(2). Under your interpretation that would mean they resolved the exponents before resolving all parentheses; shouldn't they get 8^2 instead of 4(4)? It seems you would think so, but that would be wrong. In the third step 4(4) is declared fully equivalent to 4*4, which further emphasizes my point that it's simply multiplication and not part of the parentheses step at all.
Anonymous at Fri, 24 May 2024 01:24:10 UTC No. 16190512
>>16188757
What is the best calculator for iOS, and why is it RPN48?
Anonymous at Fri, 24 May 2024 01:33:11 UTC No. 16190517
>>16188757
5/2
Anonymous at Fri, 24 May 2024 01:36:03 UTC No. 16190519
>>16190517
2.5
Anonymous at Fri, 24 May 2024 02:19:01 UTC No. 16190556
>>16188757
Oh yeah, I cannot wait to bike shed on this fascinating topic!
Anonymous at Fri, 24 May 2024 02:28:31 UTC No. 16190561
>>16190556
What does "bike shed" mean to you as a verb?
Anonymous at Fri, 24 May 2024 02:30:16 UTC No. 16190564
16190509
wow you found a wrong source so hard
no more You's
Anonymous at Fri, 24 May 2024 02:37:07 UTC No. 16190566
>>16190564
>your source is wrong
>no I won't post my own contrary evidence
>it's wrong because I say so
I accept your concession.
Anonymous at Fri, 24 May 2024 02:43:06 UTC No. 16190572
>>16190564
>>16190566
By the way, you can even type 4(5-3)^2 into a calculator and it will give you 16 rather than 64. If you care to post contrary evidence I'll consider it, but I think you know you're wrong.
Anonymous at Fri, 24 May 2024 08:48:48 UTC No. 16190819
>>16190566
>>16190572
lol so mad
still wrong btw
Anonymous at Fri, 24 May 2024 13:41:16 UTC No. 16191038
>>16190819
It's okay to just admit you were talking out of your ass, anon.
Anonymous at Fri, 24 May 2024 13:42:39 UTC No. 16191041
>>16188757
Left: SOVL
Right: soulless
>verification not required
Anonymous at Fri, 24 May 2024 17:56:39 UTC No. 16191360
>>16189629
Why whould you use a dedicated calculator
Anonymous at Fri, 24 May 2024 18:05:26 UTC No. 16191368
>>16190512
>Skeuomorphic trash
Just use Desmos.
Anonymous at Sat, 25 May 2024 07:21:56 UTC No. 16192249
>>16191360
I can play Doom with it
Anonymous at Sat, 25 May 2024 08:12:43 UTC No. 16192322
>>16191360
Muh tactile response.
Anonymous at Sat, 25 May 2024 18:27:26 UTC No. 16192900
>>16188757
I was taught, both in grade school, and in compilers when parsing shit like this, that operations of the same priority are evaluated from left to right.
It's 9
Anonymous at Sat, 25 May 2024 22:07:10 UTC No. 16193204
>>16188804
Twitter user assumes the equation is:
6
-----
2+4
However, 6/2(1+2) could both be
6
-------
2(1+2)
And
6
---- (1+2)
2
They are not the same.
Anonymous at Sun, 26 May 2024 06:37:08 UTC No. 16193666
>>16192900
Your grade school sucks ass for not teaching you PEMDAS
Anonymous at Sun, 26 May 2024 10:13:53 UTC No. 16193895
>>16191041
Sorry, I thought this thread was about physical calculators vs. calculator apps
Anonymous at Sun, 26 May 2024 12:00:04 UTC No. 16194025
>>16188757
Now sue the mobile app's maker for spreading desinformation.
Anonymous at Sun, 26 May 2024 12:55:31 UTC No. 16194106
>>16188757
on the left: properly implemented cas with well established paradigms (associativity, binding etc
on the right: pajeet cas
Anonymous at Sun, 26 May 2024 13:39:48 UTC No. 16194141
>>16189514
>>16189522
>>16189828
idg whats this point
Anonymous at Sun, 26 May 2024 13:54:46 UTC No. 16194166
>>16194141
The top one could also be represented as 6/(2(2+1)). If you put 6 over the entire expression you have to resolve everything on the bottom before dividing, but if 6 is only over 2 and not over (2+1) you divide before multiplying.
Anonymous at Sun, 26 May 2024 13:57:36 UTC No. 16194171
>>16189514
basically:
[math]6/[2(2+1)]=1[/math]
Anonymous at Sun, 26 May 2024 14:40:01 UTC No. 16194202
>>16194166
what the fuck are you even talking about
Anonymous at Sun, 26 May 2024 15:35:39 UTC No. 16194272
>>16194202
What number is /\? Fix your handwriting, for fuck's sake.
Anonymous at Sun, 26 May 2024 15:41:46 UTC No. 16194278
Anonymous at Sun, 26 May 2024 15:57:55 UTC No. 16194303
>>16194202
6/(2(2+1)) = [math]\frac{6}{2(2+1)}=\frac{6}{2(3
(6/2)*(2+1) = [math]\frac{6}{2}*(2+1)=\frac{6}{2}
>>16194141
The point is both solutions are correct but ÷ makes the equation ambiguous. It's better to write fractions
Anonymous at Sun, 26 May 2024 16:25:34 UTC No. 16194334
>>16194303
I would say the phone calculator is most correct. The graphing calculator introduces bonus assumptions about the grouping while the phone calculator requires adding additional parentheses to create such a grouping. The fewer assumptions a calculator makes, the better.
Anonymous at Sun, 26 May 2024 16:37:33 UTC No. 16194349
>>16189514
6/2*(2+1) is not the same as 6/[2*(2+1)]
Anonymous at Sun, 26 May 2024 16:38:34 UTC No. 16194351
>>16194303
>The point is both solutions are correct
NO!
See:
>>16194349
Anonymous at Sun, 26 May 2024 18:13:30 UTC No. 16194480
>>16193666
PEMDAS does not mean multiplication before division. It's more like PE(MD)(AS).
Anonymous at Sun, 26 May 2024 18:43:35 UTC No. 16194527
>>16194480
When I learned it in school the teacher wrote it out vertically so it seemed more like a tiered ranking system.
P
E
MD
AS
This visual stuck with me well, all teachers should do this.
Anonymous at Sun, 26 May 2024 18:46:49 UTC No. 16194537
>>16194480
If you have 2(2+1), you must eliminate the parentheses first. This means (4+2) -> 6
It can't be that hard
Anonymous at Sun, 26 May 2024 19:41:54 UTC No. 16194607
>>16194334
It might also depend on your region. In australia we are taught multiplication and division are the same tier and whichever is leftmost goes first. so without fractions it would be
6÷2(2+1) = 6÷2*3 = 3*3 = 9
https://www.australiancurriculum.ed
>>16194349
it is if you use ÷ . I'm trying to explain why they are getting different answers. the phone and calculate are interpreting the fractions differently which is causing this discrepancy
>>16194351
>NO!
i'll admit 9 is the better answer (in my country at least) but you could also interpret it as 6/[2*(2+1)] since the ÷ is ambiguous. in other words the question is wrong, just use fractions and this madness will end
Anonymous at Sun, 26 May 2024 19:47:05 UTC No. 16194613
>>16194607
>In australia we are taught multiplication and division are the same tier and whichever is leftmost goes first.
That's just how the order of operations works, if anyone was taught differently in another region they were simply taught wrong. The problem with the graphing calculator in OP is that it assumes anything to the right of the ÷ symbol should be grouped as the denominator in a fraction, which in my opinion is a faulty assumption that takes agency away from the human using the calculator.
Anonymous at Sun, 26 May 2024 22:15:58 UTC No. 16194844
>>16194537
it's not, but it apparently is for you.
6 / 2 * (2 + 1)
evaluate parenthesis
= 6 / 2 * 3
division and multiplication has same priority, so goes left to right
= 3 * 3 = 9
Anonymous at Sun, 26 May 2024 22:27:59 UTC No. 16194871
>>16194795
The one on the right is wrong because it automatically groups (2(2+1)) as the entire part of a fraction's denominator despite there not being notation to do so. This makes its logic inflexible and reduces functionality.
🗑️ Anonymous at Sun, 26 May 2024 22:29:11 UTC No. 16194873
>>16194537
In your mind 2(2+1) = (4+2)? You need to go back to Algebra 1, son.
Anonymous at Sun, 26 May 2024 22:57:00 UTC No. 16194903
>>16194871
The right one actually gives a different answer depending on whether it's 2(2+1) or 2x(2+1). So for some reason whoever programmed it decided that 2(2+1) is always the same as (2(2+1)).
Anonymous at Sun, 26 May 2024 23:16:12 UTC No. 16194933
>>16194903
I guess that's not too bad. At least it has available syntax for un-grouping them.
Anonymous at Mon, 27 May 2024 00:13:05 UTC No. 16195017
>>16194607
>whichever is leftmost goes first
That's the issue. Any equation which relies on the left to right distinction is a faulty question. The only reason why the left to right distinction is needed is because ÷ is a shit symbol. No other equation ever needs to be read left to right when ÷ isn't involved.
Schools dumb shit down and teach everyone wrong to try and make it "simpler".
The reason why people answer 1 is because normally that would how someone who un-retardified their brain and stopped using ÷ would answer the question, with 6 as the numerator and the rest of the equation as the denominator. But because ÷ is in play, you have to kill off brain cells and do grug maths instead.
Anonymous at Mon, 27 May 2024 01:09:41 UTC No. 16195075
>>16195017
>maths
Opinion disregarded.
Anonymous at Mon, 27 May 2024 01:52:14 UTC No. 16195122
>>16191368
>Just use Desmos.
Why?
Anonymous at Mon, 27 May 2024 02:35:36 UTC No. 16195166
>>16188757
echo $EXPRESSION | bc
is the obvious choice
Anonymous at Mon, 27 May 2024 09:02:43 UTC No. 16195490
>>16188757
6/2(2+1)
6/(4+2)
(6/4)+(6/2)
(3/2)+(6/2)
9/2
Anonymous at Tue, 28 May 2024 06:24:04 UTC No. 16197190
>>16195490
Holy schizola cringola
Anonymous at Tue, 28 May 2024 07:08:59 UTC No. 16197269
>>16188757
991CW automatically converts 6÷2(1+2) to 6÷(2(1+2)), if you try to solve it, use a better calculator, semantic ambiguities like this aren't math.
Anonymous at Tue, 28 May 2024 07:36:46 UTC No. 16197325
>>16197269
>semantic ambiguities
nah, just idiots
'÷' = '/' for anyone with an iq over room temperature
Anonymous at Tue, 28 May 2024 08:19:30 UTC No. 16197366
>>16194303
>The point is both solutions are correct
Those are two different problems. And 6/2(2+1) only means one of them.
Only one solution is correct for that problem.
This is tantamount to arguing it's could mean its or it is. No. It only means it is. And if you argue it's ambiguous, you're just an idiot.
People not knowing how to read and write doesn't make something ambiguous whether we're talking math or English.
Anonymous at Tue, 28 May 2024 08:28:45 UTC No. 16197380
>>16194795
>So... one of them has been programmed wrong?
No. You have implied multiplication grouping turned on. Go into settings and turn it off.
It's between "Thousands separator" and "Default output".
On a related note, even if you had known how to properly use a calculator, which you don't, calculators don't have to obey the standard order of operations. It doesn't mean that they're programmed wrong, albeit they should mention they use nonstandard notation in their manuals if they do so.
Anonymous at Tue, 28 May 2024 08:39:08 UTC No. 16197395
>>16189547
It's implicit multiplication, not implicit parentheses. All 2(1+2) implies is 2*(1+2). Fractions are what have implicit parentheses.
Anonymous at Tue, 28 May 2024 08:56:36 UTC No. 16197415
>>16188757
Problem?
Anonymous at Wed, 29 May 2024 05:49:49 UTC No. 16198723
>>16188801
Elaborate.
Anonymous at Wed, 29 May 2024 06:05:23 UTC No. 16198749
>>16197415
yuhh fellow fx-991cw user such based calculator
Anonymous at Wed, 29 May 2024 06:08:12 UTC No. 16198750
Stop trying to do two things at once!
Anonymous at Wed, 29 May 2024 08:19:08 UTC No. 16198860
>>16198723
6 2 2 1 + * / = 6 2 3 * / = 6 6 / = 1
or simpler
6 2 1 + 2 * / = 6 3 2 * / = 6 6 / = 1
6 2 / 2 1 + * = 3 3 * = 9
no ambiguity, each operator always takes the required operands from the top of the stack, performs operation and puts result on top of the stack. 3÷3(6) type problems are a problem because they're written in purposfully undefined notation (÷ is used only by grade schoolers), RNP is made to be written inline, hence it does not have the problem of two types of division (inline a ÷ b and fractional a/b). RNP has no implicit order changes, it's not fun for algebra and writting physics formulas for eg. but for airthmetic (calculators) it should be the standard
Anonymous at Wed, 29 May 2024 08:29:51 UTC No. 16198872
>>16198860
>in purposfully undefined notation (÷ is used only by grade schoolers)
>claims something is undefined
>immediately says it IS defined and is defined so well a grade schooler could understand it
Like claiming "rizz" is undefined. FFS.
Anonymous at Wed, 29 May 2024 08:43:09 UTC No. 16198884
>>16190512
>iOS
you can leave now
white man's board, sorry not sorry
Anonymous at Wed, 29 May 2024 10:02:54 UTC No. 16198944
>>16198749
I like it but I liked my fx-991EX more. It kinda died
Anonymous at Thu, 30 May 2024 03:23:58 UTC No. 16200176
>>16198860
Oh, I've only ever read it being called postfix notation, It is nice but its not intuitive for human parsing, just machines
Anonymous at Thu, 30 May 2024 10:15:08 UTC No. 16200548
>>16198872
is ÷ is defined as simple inline division, but we only ever write a+b(c+d) or a-b(c+d), and division is done by making the whole expression a fraction, that's why inline div with parentheses multiplication is weird hence "undefined" I dont know the proper order, it depends on whether a(b) has implicit aditional parentheses, but I dont care because no one has that problem in real math
>>16200176
it is intuitive, I've been using dc - linux RNP terminal calculator - for some time now and there is no learninf curve. Thinking '21 37 add' is as natural as infix notation. Some languages like latin usually place the verb at the end, functionally using postfix notation in speech. The RNP stack is itself very useful, no need for akward 'save' button on your infix calculator
Anonymous at Thu, 30 May 2024 15:12:06 UTC No. 16200875
>>16188757
It is customary to go left to right, the exception are parentheses so it's 9.
This problem is extremely fucking stupid, the notation is flawed and unintuitive but people are trying to find an objective answer to this question instead of accepting a simple fact of flawed notation.
Anonymous at Thu, 30 May 2024 19:07:02 UTC No. 16201207
>>16200548
>division is done by making the whole expression a fraction
It isn't. It's a binary operator that acts on the two adjacent values, same as *,+, and -. Which is why you can solve a÷b÷c with ease.
>it depends on whether a(b) has implicit aditional parentheses
It doesn't unless specified. Conventional order of operations treats a*b, ab, axb, and a(b) as the same with regards to the priority of the multiplication. It's BODMAS, not BOMDMAS.
Anonymous at Thu, 30 May 2024 19:47:02 UTC No. 16201254
>>16200875
>It is customary to go left to right
It's customary to go in the order of the priority of the operations.
So a full order of operations would be
>Parentheses, numerators, denominators, fractions, and functions smallest to largest, top to bottom, left to right
>Hyperoperations tetration and above in descending order, smallest to largest, left to right
>Exponentiation smallest to largest, right to left
>Multiplication and division left to right
>Addition and subtraction left to right
PNDFFHEMDAS if you will.
Typing this out made me yearn for death.