Mastodawn

SSUPII Nov 27

I feel like I am getting trolled

Isn’t 17 the actual right answer?

pixeltree Nov 27

Inside the parens first, so it becomes 2 + 5*3

Then tou do multiplication before addition, so 2 + 15

Then addition, so 17

SSUPII Nov 27

Yeah I know that. But I was feeling confused as to why it was here. That’s why I was feeling trolled, because it made me doubt basic math for being posted in a memes community.

JackbyDev Nov 27

They did the joke wrong. To do it right you need to use the ÷ symbol. Because people never use that after they learn fractions, people treat things like a + b ÷ c + d as

a + b ----- c + d

Or (a + b) ÷ (c + d) when they should be treating it as a + (b ÷ c) + d.

That’s the most common one of these “troll math” tricks. Because notating as

a + b + d - c

Is much more common and useful. So people get used to grouping everything around the division operator as if they’re in parentheses.

CannonFodder

Or
12 / 2(6) And trying to argue this is 36.

MotoAsh Nov 27

Well, now you might be running into syntax issues instead of PEMDAS issues depending on what they’re confused about. If it’s 12 over 2*6, it’s 1. If it’s 12 ÷ 2 x 6, it’s 36.

A lot of people try a bunch of funky stuff to represent fractions in text form (like mixing spaces and no spaces) when they should just be treating it like a programmer has to, and use parenthesis if it’s a complex fraction in basic text form.

Feathercrown Nov 27

The P in PEMDAS means to solve everything within parentheses first; there is no “distribution” step or rule that says multiplying without a visible operator other than parentheses comes first. So yes, 36 is valid here. It’s mostly because PEMDAS never shows up in the same context as this sort of multiplication or large fractions

💡𝚂𝗆𝖺𝗋𝗍𝗆𝖺𝗇 𝙰𝗉𝗉𝗌📱Dec 14

The P in PEMDAS means to solve everything within parentheses first

and without a(b+c)=(ab+ac), now solve (ab+ac)

there is no “distribution” step or rule

It’s a LAW of Maths actually, The Distributive Law.

that says multiplying without a visible operator

It’s not “Multiplying”, it’s Distributing, a(b+c)=(ab+ac)

So yes, 36 is valid here

No it isn’t. To get 36 you have disobeyed The Distributive Law, thus it is a wrong answer

It’s mostly because

people like you try to gaslight others that there’s no such thing as The Distributive Law

Feathercrown Dec 15

Are you under the impression that atomizing your opponents statements and making a comment about each part individually without addressing the actual point (how those facts fit together) is a good debate tactic? Because it seems like all you’ve done is confuse yourself about what I was saying and make arguments that don’t address it.

addressing the actual point (how those facts fit together)

I did address the actual point - see Maths textbooks

all you’ve done is confuse yourself

I’m not confused at all. I’m the one who knows the difference between Distribution and Multiplication.

what I was saying

You lied about there being no such thing as “the Distribution step” (Brackets), proven wrong by the textbooks

make arguments that don’t address it.

Textbooks talking about The Distributive Law totally addresses your lie that no such step exists.

Never mind that some of those micro-rebuttals aren’t even correct

You think Maths textbooks aren’t correct?? 😂

Feathercrown Dec 15

I have said why this style of debate is bad in greater detail here: lemmy.world/post/39377635/21030374

But to make a pointless effort to address your actual point, yes distribution exists, no it is not a step in PE(MD)(AS). Again, you have not understood my point because you categorically fail to engage with any argument. I don’t think you even understand what it means to do so. I will not respond further to either thread.

I dunno - Lemmy.World

Lemmy

💡𝚂𝗆𝖺𝗋𝗍𝗆𝖺𝗇 𝙰𝗉𝗉𝗌📱Dec 16

I have said why this style of debate is bad in greater detail here: lemmy.world/post/39377635/21030374

Which I debunked here

no it is not a step in PE(MD)(AS)

So… you’re saying the “P” step in PEMDAS isn’t a step in PEMDAS?? This is hilarious given you were just talking about contradictions 😂

Again, you have not understood my point

Maybe because saying the “P” step in PEMDAS isn’t a step in PEMDAS makes no sense at all 😂

you categorically fail to engage with any argument.

No, I comprehensively debunked all of your points and deflections. 😂

I don’t think you even understand what it means to do so

says person who keeps avoiding the textbook screenshots and worked examples proving them wrong

I will not respond further to either thread

Yay! Don’t let the door hit you on the way out 😂

I dunno - Lemmy.World

Lemmy

Feathercrown Dec 16

Parentheses means evaluating the things inaide the parentheses you nimrod

💡𝚂𝗆𝖺𝗋𝗍𝗆𝖺𝗇 𝙰𝗉𝗉𝗌📱Dec 16

Parentheses means evaluating the things inside the parentheses you nimrod

Only if you’re still in Elementary school. How old are you anyway? Here’s a high school Algebra book, you know, after students have been taught The Distributive Law…

JackbyDev Nov 27

Now that’s a good troll math thing because it gets really deep into the weeds of mathematical notation. There isn’t one true order of operations that is objectively correct, and on top of that, that’s hardly the way most people would write that. As in, if you wrote that by hand, you wouldn’t use the / symbol. You’d either use ÷ or a proper fraction.

It’s a good candidate for nerd sniping.

Personally, I’d call that 36 as written given the context you’re saying it in, instead of calling it 1. But I’d say it’s ambiguous and you should notate in a way to avoid ambiguities. Especially if you’re in the camp of multiplication like a(b) being different from ab and/or a × b.

Nerd Sniping

xkcd

💡𝚂𝗆𝖺𝗋𝗍𝗆𝖺𝗇 𝙰𝗉𝗉𝗌📱Dec 14

There isn’t one true order of operations that is objectively correct

Yes there is, as found in Maths textbooks the world over

that’s hardly the way most people would write that

Maths textbooks write it that way

you wouldn’t use the / symbol

Yes you would.

You’d either use ÷

Same same

It’s a good candidate for nerd sniping.

Here’s one I prepared earlier to save you the trouble

I’d call that 36

And you’d be wrong

as written given the context you’re saying it in

The context is Maths, you have to obey the rules of Maths. a(b+c)=(ab+ac), 5(8-5)=(5x8-5x5).

But I’d say it’s ambiguous

And you’d be wrong about that too

you should notate in a way to avoid ambiguities

It already is notated in a way that avoids all ambiguities!

Especially if you’re in the camp of multiplication like a(b)

That’s not Multiplication, it’s Distribution, a(b+c)=(ab+ac), a(b)=(axb).

being different from ab

Nope, that’s exactly the same, ab=(axb) by definition

and/or a × b

(axb) is most certainly different to axb. 1/ab=1/(axb), 1/axb=b/a

💡𝚂𝗆𝖺𝗋𝗍𝗆𝖺𝗇 𝙰𝗉𝗉𝗌📱 (@[email protected])

1/3 #MathsMonday Order of operations thread index #Mathematics #Maths #Math Introduction https://dotnet.social/@SmartmanApps/110807192608472798 1 The Distributive Law #DontForgetDistribution https://dotnet.social/@SmartmanApps/110819283738912144 2 Terms #MathsIsNeverAmbiguous https://dotnet.social/@SmartmanApps/110846452267056791 3 Factorising<->The Distributive Law https://dotnet.social/@SmartmanApps/110886637077371439 4 implicit multiplication, mnemonics https://dotnet.social/@SmartmanApps/110925761375035558 5 1917 (i) - Left Associativity https://dotnet.social/@SmartmanApps/110965810374299599 6 1917 (ii) - Lennes' letter (Terms and operators) https://dotnet.social/@SmartmanApps/111005247356655843 ...

dotnet.social

en.wikipedia.org/wiki/Order_of_operations#Mixed_d…

JackbyDev Dec 14

Please read this section of Wikipedia which talks about these topics better than I could. It shows that there is ambiguity in the order of operations and that for especially niche cases there is not a universally accepted order of operations when dealing with mixed division and multiplication. It addresses everything you’ve mentioned.

There is no universal convention for interpreting an expression containing both division denoted by ‘÷’ and multiplication denoted by ‘×’. Proposed conventions include assigning the operations equal precedence and evaluating them from left to right, or equivalently treating division as multiplication by the reciprocal and then evaluating in any order;[10] evaluating all multiplications first followed by divisions from left to right; or eschewing such expressions and instead always disambiguating them by explicit parentheses.[11]

Beyond primary education, the symbol ‘÷’ for division is seldom used, but is replaced by the use of algebraic fractions,[12] typically written vertically with the numerator stacked above the denominator – which makes grouping explicit and unambiguous – but sometimes written inline using the slash or solidus symbol ‘/’.[13]

Multiplication denoted by juxtaposition (also known as implied multiplication) creates a visual unit and is often given higher precedence than most other operations. In academic literature, when inline fractions are combined with implied multiplication without explicit parentheses, the multiplication is conventionally interpreted as having higher precedence than division, so that e.g. 1 / 2n is interpreted to mean 1 / (2 · n) rather than (1 / 2) · n.[2][10][14][15] For instance, the manuscript submission instructions for the Physical Review journals directly state that multiplication has precedence over division,[16] and this is also the convention observed in physics textbooks such as the Course of Theoretical Physics by Landau and Lifshitz[c] and mathematics textbooks such as Concrete Mathematics by Graham, Knuth, and Patashnik.[17] However, some authors recommend against expressions such as a / bc, preferring the explicit use of parenthesis a / (bc).[3]

More complicated cases are more ambiguous. For instance, the notation 1 / 2π(a + b) could plausibly mean either 1 / [2π · (a + b)] or [1 / (2π)] · (a + b).[18] Sometimes interpretation depends on context. The Physical Review submission instructions recommend against expressions of the form a / b / c; more explicit expressions (a / b) / c or a / (b / c) are unambiguous.[16]

6÷2(1+2) is interpreted as 6÷(2×(1+2)) by a fx-82MS (upper), and (6÷2)×(1+2) by a TI-83 Plus calculator (lower), respectively.

This ambiguity has been the subject of Internet memes such as “8 ÷ 2(2 + 2)”, for which there are two conflicting interpretations: 8 ÷ [2 · (2 + 2)] = 1 and (8 ÷ 2) · (2 + 2) = 16.[15][19] Mathematics education researcher Hung-Hsi Wu points out that “one never gets a computation of this type in real life”, and calls such contrived examples “a kind of Gotcha! parlor game designed to trap an unsuspecting person by phrasing it in terms of a set of unreasonably convoluted rules”.[12]

Order of operations - Wikipedia

💡𝚂𝗆𝖺𝗋𝗍𝗆𝖺𝗇 𝙰𝗉𝗉𝗌📱Dec 14

Please read this section of Wikipedia which talks about these topics better than I could

Please read Maths textbooks which explain it better than Joe Blow Your next Door neighbour on Wikipedia. there’s plenty in here

It shows that there is ambiguity in the order of operations

and is wrong about that, as proven by Maths textbooks

especially niche cases there is not a universally accepted order of operations when dealing with mixed division and multiplication

That’s because Multiplication and Division can be done in any order

It addresses everything you’ve mentioned

wrongly, as per Maths textbooks

Multiplication denoted by juxtaposition (also known as implied multiplication)

Nope. Terms/Products is what they are called. “implied multiplication” is a “rule” made up by people who have forgotten the actual rules.

s often given higher precedence than most other operations

Always is, because brackets first. ab=(axb) by definition

1 / 2n is interpreted to mean 1 / (2 · n)

As per the definition that ab=(axb), 1/2n=1/(2xn).

[2][10][14][15]

Did you look at the references, and note that there are no Maths textbooks listed?

the manuscript submission instructions for the Physical Review journals

Which isn’t a Maths textbook

the convention observed in physics textbooks

Also not Maths textbooks

mathematics textbooks such as Concrete Mathematics by Graham, Knuth, and Patashnik

Actually that is a Computer Science textbook, written for programmers. Knuth is a very famous programmer

More complicated cases are more ambiguous

None of them are ambiguous.

the notation 1 / 2π(a + b) could plausibly mean either 1 / [2π · (a + b)]

It does as per the rules of Maths, but more precisely it actually means 1 / (2πa + 2πb)

or [1 / (2π)] · (a + b).[18]

No, it can’t mean that unless it was written (1 / 2π)(a + b), which it wasn’t

Sometimes interpretation depends on context

Nope, never

more explicit expressions (a / b) / c or a / (b / c) are unambiguous

a/b/c is already unambiguous - left to right. 🙄

Image of two calculators getting different answers

With the exception of Texas Instruments, all the other calculator manufacturers have gone back to doing it correctly, and Sharp have always done it correctly.

6÷2(1+2) is interpreted as 6÷(2×(1+2))

6÷(2x1+2x2) actually, as per The Distributive Law, a(b+c)=(ab+ac)

(6÷2)×(1+2) by a TI-83 Plus calculator (lower)

Yep, Texas Instruments is the only one still doing it wrong

This ambiguity

doesn’t exist, as per Maths textbooks

“8 ÷ 2(2 + 2)”, for which there are two conflicting interpretations:

No there isn’t - you MUST obey The Distributive Law, a(b+c)=(ab+ac)

Mathematics education researcher Hung-Hsi Wu points out that “one never gets a computation of this type in real life”

And he was wrong about that. 🙄

calls such contrived examples

Which notably can be found in Maths textbooks

💡𝚂𝗆𝖺𝗋𝗍𝗆𝖺𝗇 𝙰𝗉𝗉𝗌📱 (@[email protected])

dotnet.social

JackbyDev Dec 14

If you believe the article is incorrect, submit your corrections to Wikipedia instead of telling me.

If you believe the article is incorrect, submit your corrections to Wikipedia

You know they’ve rejected corrections by actual Maths Professors right? Just look for Rick Norwood in the talk section. Everyone who knows Maths knows Wikipedia is wrong, and looks in the right place to begin with - Maths textbooks

Again, if you have a problem with Wikipedia, take it up with Wikipedia.

Again, if you have a problem with Wikipedia, take it up with Wikipedia

You’ve made the mistake of thinking they care. Again, look for Rick Norwood in the Talk sections, an actual Maths professor (bless him for continually trying to get them to correct the mistakes though)

Take it up with them if you have a problem with them.

Take it up with them if you have a problem with them

I see you’re not even reading what I said. No wonder you don’t know how to do Maths…

I did read everything you said and I do know how to do math. I hope you are able to enact the change you want to see in Wikipedia and the article. Good luck.

I did read everything you said

Clearly you didn’t, given you keep telling me to take it up with Harvard/Wiki

enact the change you want to see in Wikipedia

See?? There you go again ignoring what I told you about Wikipedia 🙄

I haven’t ignored anything you said. I’m telling you that if you have a problem with those that you should contact them to fix them.

I haven’t ignored anything you said.

You’ve ignored everything I’ve said about Wikipedia.

I’m telling you that if you have a problem with those that you should contact them to fix them

and you have again ignored what I told you about them 🙄

It’s funny that you define “ignore” as “not doing what you tell someone to” because by that definition you’ve been ignoring me too. Go edit the article if you feel this strongly.

It’s funny that you define “ignore” as “not doing what you tell someone to”

Nope, I didn’t.

because by that definition you’ve been ignoring me too

I’m ignoring the person failing to cite Maths textbooks, yes, that’s correct.

Go edit the article if you feel this strongly

Go read what I said about what happens when ACTUAL MATHS PROFESSORS have tried to do EXACTLY THAT 🙄

Go tell Wikipedia about that, not me. It’s a community you can join. You very clearly feel very strongly about it. Talking to me about it isn’t going to change anything.