This kind of problem falls under “communicating badly and acting smug when misunderstood”. Use parenthesis and the problem goes away.
This kind of problem falls under “communicating badly and acting smug when misunderstood”.
No it doesn’t. It falls under adults forgetting the rules of Maths.
Use parenthesis and the problem goes away
There is no problem, other than adults who have forgotten the rules.
on that note, can we please have parentheses in language. i keep making ambiguous sentences
My language teachers always told me it was bad form to use too much or even to nest parenthesis…
Then I found lisp…
Lost In Stupid Parenthesis.
We have them in written language, though?
Isn’t that basically what commas are for?
Why (I don’t see) not
This is why grammar is important, and “grammar nazis” are the only good kind of nazis.
People try and use commas for this sort of clarification and are eviscerate for it.
With these sort of math problems, the rules are taught early and then all subsequent math is written in an unambiguous form.
Language has the oddity of going the other way around where the rules get more complex as a display for advanced skills.
eviscerated
God, can you even spell???
Get your act together./s
What’s the scam?
OK, it’s been a few hours. I’ll do the clumsy thing that everyone else has avoided and point out that it’s deliberately set up so that people who have never heard of operator precedence - those who do things purely left-to-right - don’t get a weird fraction when the division step is done, making them think that the answer they’ve reached must be the right one. You’d still get a handful who’d argue regardless, but that whole number ropes in a whole bunch more.
Couple that with the fact that the value reached this way doesn’t match the value obtained from using operator precedence and you get arguments about what the right answer is. And a comment like the one you’re reading right now that’s too long for the hard-of-thinking to read.
“More engagement, baybee [sunglasses smiley emoji] [cash bag emoji]” etc.
11
deleted by creator
Not strictly a scam, but there’s a little money to be made creating viral content on Facebook. They receive a tiny portion of the ad revenue from Facebook when they generate engagement.
It’s just Facebook sucking really.
Thanks 🙏
I was good at math and it was one of my favorite core subjects in school, so I know I’m a weirdo but… I never understood how people couldn’t understand basic PEMDAS/BEDMAS/Whatever-the-fuck-your-country-calls-it.
Obviously these problems are shitty engagement bait because they don’t use parentheses, but still, seeing people fuck up the fact that Multiplication AND Division occur at the same time, and then the next step is Addition AND Subtraction just stupefies me.
Like, did you sleep through 4 years of elementary school to miss that fact??? Even in middle school pre-algebra teachers still did PEMDAS refreshers. I get that once I get out of college I’m probably gonna forget half the pre-calc shit I learned because I won’t need it, and I’m not being drilled on it everyday like people in school are, but PEMDAS is a fundamental and basic daily life skill that everyone should know…
I really wish we gave a fuck about US education.
I never understood how people couldn’t understand basic PEMDAS/BEDMAS/Whatever-the-fuck-your-country-calls-it.
There’s no “whatever-the-fuck-your-country-calls-it”, the US is the only country using it, and only up to high school. At least I’m not seeing any papers coming out of the US relying on it so at some point they’re dropping it and do what everyone else is doing: Write equations such that you don’t need a left-to-right rule to disambiguate things. Also, using multiplication by juxtaposition (2x + 4x2).
There’s no “whatever-the-fuck-your-country-calls-it”
Yes there is. BEDMAS, BODMAS, and BIDMAS
the US is the only country using it
No they’re not.
at some point they’re dropping it
No, at no point do the order of operations rules ever get dropped
using multiplication by juxtaposition (2x + 4x2)
They’re called Terms/Products.
I was bad at math, but I still managed to get through precal and still remember PEMDAS
For me it’s the arguments when there is a parentheses but no operator (otherwise known as implied multiplication) in these baits e.g. 15 + 2(4 - 2)
If you don’t know operator orders I have given up long ago, but I have seen a few lengthy discussions about this
Oh yeah, that’s a fun one.
Where I live, this would be considered juxtaposition, at least by uni professors and scientific community, so 2(4-2) isn’t the same as 2×(4-2), even though on their own they’re equal.
This way, equations such as 15/2(4-2) end up with a definite solution.
So,
15/2(4-2) = 3.75
While
15/2×(4-2) = 15
Usually, however, it is obvious even without assuming juxtaposition because you can look at previous operations. Not to mention that it’s most common with variables (Eg. “2x/3y”).
Where I live, this would be considered juxtaposition
Not just where you live, everywhere, in Maths textbooks. Adults forgetting the rules (and unqualified U.S. teachers not teaching what’s in the textbooks) is another matter altogether.
For me it’s the arguments when there is a parentheses but no operator (otherwise known as implied multiplication)
No, it’s known as Factorised Terms/Products, solved via The Distributive Law, a(b+c)=(ab+ac). “implied multiplication” is a made up rule by people who have forgotten the actual rules, and often they get it wrong (because, having wrongly called it “multiplication”, they then wrongly give it the precedence of multiplication, not brackets).
question: is there something more than the expression evaluating to 11?
This thread shows that a whole bunch of people need to start taking online education courses. Getting back your algebra skills, some science perhaps, communication, history, etc.
I don’t know where you can get a proper education for that after grade school, but I see Brilliant.org advertised a lot.
This is the kind of post designed to invoke a reaction. Facebook’s and pretty much every other algorithm driven social media is designed to promote posts that have high interaction. So a post that invokes lots of negative reactions gets lots of promotion. Hence the downfall of modern society.
"Hey, this is Presh Talwalkar.
discussion of a brief history of this viral math problem, followed by explanations of common incorrect answers. Finally followed by brief discussion on the order of operations, concluding in a final example that ultimately equals 11And that’s the answer. Thank you so much for making us one of the best communities on YouTube, where we solve the world’s problems, one video at a time."
Hey, this is Presh Talwalkar
Person who has forgotten about The Distributive Law and lied about 1917.
Discussion of a brief history of this viral math problem
Including lying about 1917
Ultimately followed by brief discussion on the order of operations
But forgets about Terms and The Distributive Law.
And that’s the answer
Now watch his other ones, where he screws it up royally. Dude has no idea how to handle brackets. Should be avoided at all costs.
I’ve seen many of his videos and haven’t noticed any obvious errors. Could you please link to the specific video(s) that you are referencing in regards to errors he has made, especially those related to the distributive law and what you reference to as “1917,” as well as any explanation as to what is incorrect/misleading/lying?
I’ve seen many of his videos and haven’t noticed any obvious errors.
He makes mistakes every time there’s Brackets with a Coefficient. He always does a(b)=axb, instead of a(b)=(axb), hence wrong every time it follows a division.
what you reference to as “1917,”
No, he calls it that, though sometimes he also tries to claim it’s an article (it isn’t - it was a letter) - he never refers to Lennes by name. He also ignores what it actually says, and in fact disobeys it (the rule proposed by Lennes was to do all multiplication first, and yet he proceeds to do the division first, hence wrong answer, even though he just claimed that 1917 is the current rule).
Here’s a thread about Lennes’ 1917 letter, including a link to an archived copy of it.
Here’s where Presh Talwalker lied about 1917
Here’s a thread about The Distributive Law
Here’s where Presh Talwalker disobeyed The Distributive Law (one of many times) (he does 2x3 instead of (2x3), hence gets the wrong answer). What he says is the “historical” rule in “some” textbooks, is still the rule and is used in all textbooks, he just never looked in any!
Note that, as far as I can tell, he doesn’t even have any Maths qualifications. He keeps saying “I studied Maths at Harvard”, and yet I can find no evidence whatsoever of what qualifications he has - I suspect he dropped out, hence why he keeps saying “I studied…”. In one video he even claimed his answer was right because Google said so. I’m not kidding! He’s a snake oil salesman, making money from spreading disinformation on Youtube - avoid at all cost. There are many freely-available Maths textbooks on the Internet Archive if you want to find proof of the truth (some of which have been quoted in the aforementioned thread).
Thank you very much for the detailed response! Very informative and interesting.
Boomers and Xgens need to prove, that they remember basic school math in FB lmao.
Who, the people who never had calculators in their pockets growing up? No worries, we can do math better than you.
lmao
Knowing basic arithmetic does not mean you know Math, and the fact you so hung up about this trivial aspect says a lot about you. Additionally, you express yourself like a boomer.
I’m more worried about the gratuitous comma and what it means for the state of education.
What, gratuitous, comma?
The one after the prove.
Nah, people can write things while being a bit drunk, you know. I’m speaking for a friend, not me, ofc.
Gen xers? Don’t irk them. They’re not noticing you right now.
Very independent, and cranky generation.
Please don’t include X with the boomers. Since we stepped into the real world and realized it functions completely differently than what we were raised to believe, life’s just been a neverending string of “wait, that was wrong too?” We just want to survive another day under the radar.
Sorry fellow X’rs for publicly acknowledging our existence. Hopefully this post doesn’t get any upvotes. *Pulls blanket back over my head.
The first rule of gen-x is you don’t talk about gen-x!
The average home buyer in the US 17 years ago was born in 1968. Today? 1968. Yeah excuse me but as an elder millennial, Gen X can mostly fuck right off.
You understand that gen x starts around 1965, right? Your stat says they’re mostly getting fucked too.
You understand that gen x starts around 1965, right?
10 years earlier than that actually. Johnny Rotten, Billy Idol, etc. The U.S. came late to the party and started using their own definition.
And you understand that 68 is after 65? They’re not getting. Fucked, they’re the last ones to be able to afford housing ownership. If the average is 68 that means one side of the bell curve extends well into the generation.
As a millennial, I’m starting to relate more and more. The world changes very quickly, and all of the sudden things you knew as fact have different meanings, and there are new words and stuff. It’s not all bad change, but it’s change, and odds are, I’m finding out something changed the hard way.
Seriously, I was raised with so much propaganda.
Up until my late twenties I had believed basically everything I was taught in school. I never had reason to question it, as I was basically living in a bubble. Imagine my surprise when I discovered that when the colonists arrived to this country, it wasn’t just big empty open spaces that the native Americans gladly shared with us. Funny enough, that’s roughly when I gained access to the internet.
So order of operations is hard?
Yeah and I’m tired of pretending it’s not!
The issue normally with these “trick” questions is the ambiguous nature of that division sign (not so much a problem here) or people not knowing to just go left to right when all operators are of the same priority. A common mistake is to think division is prioritised above multiplication, when it actually has the same priority. Someone should have included some parenthesis in PEDMAS aka. PE(DM)(AS) 😄
The issue normally with these “trick” questions
There’s no “trick” - it’s a straight-out test of Maths knowledge.
the ambiguous nature of that division sign
Nothing ambiguous about it. The Term of the left divided by the Term on the right.
A common mistake is to think division is prioritised above multiplication
It’s not a mistake. You can do them in any order you want.
when it actually has the same priority
Which means you can do them in any order
“A common mistake is to think division is prioritised above multiplication”
That is what I said. I said it’s a mistake to think one of them has a precedence over the other. You’re arguing the same point I’m making?
I said it’s a mistake to think one of them has a precedence over the other
And I said it’s not a mistake. You still get the right answer.
You’re arguing the same point I’m making?
No, I’m telling you that prioritising either isn’t a mistake. Mistakes give wrong answers. Prioritising either doesn’t give wrong answers.
Another common issue is thinking “parentheses go first” and then beginning by solving the operation beside them (mostly multiplication). The point being that what’s inside the parentheses goes first, not what’s beside them.
Another common issue is thinking “parentheses go first”
There’s no “think” - it’s an absolute rule.
then beginning by solving the operation beside them
a(b) isn’t an operation - it’s a Product. a(b)=(axb) per The Distributive Law.
(mostly multiplication)
NOT Multiplication, a Product/Term.
The point being that what’s inside the parentheses goes first, not what’s beside them
Nope, it’s the WHOLE Bracketed Term. a/bxc=ac/b, but a/b( c )=a/(bxc). Inside is only a “rule” in Elementary School, when there isn’t ANYTHING next to them (students aren’t taught this until High School, in Algebra), and it’s not even really a rule then, it’s just that there isn’t anything ELSE involved in the Brackets step than what is inside (since they’re never given anything on the outside).
The same priority operations can be done in any order without affecting the result, that’s why they can be same priority and don’t need an explicit order.
6 × 4 ÷ 2 × 3 ÷ 9 evaluates the same regardless of order. Can you provide a counter example?
So let’s try out some different prioritization systems.
Left to right:
(((6 * 4) / 2) * 3) / 9 ((24 / 2) * 3) / 9 (12 * 3) / 9 36 / 9 = 4Right to left:
6 * (4 / (2 * (3 / 9))) 6 * (4 / (2 * 0.333...)) 6 * (4 / 0.666...) 6 * 6 = 36Multiplication first:
(6 * 4) / (2 * 3) / 9 24 / 6 / 9Here the path divides again, we can do the left division or right division first.
Left first: (24 / 6) / 9 4 / 9 = 0.444... Right side first: 24 / (6 / 9) 24 / 0.666... = 36And finally division first:
6 * (4 / 2) * (3 / 9) 6 * 2 * 0.333... 12 * 0.333.. = 4It’s ambiguous which one of these is correct. Hence the best method we have for “correct” is left to right.
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.
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.
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.
Maybe I’m wrong but the way I explain it is until the ambiguity is removed by adding in extra information to make it more specific then all those answers are correct.
“I saw her duck”
Until the author gives me clarity then that sentence has multiple meanings. With math, it doesn’t click for people that the equation is incomplete. In an English sentence, ambiguity makes more sense and the common sense approach would be to clarify what the meaning is
100% with you. “Left to right” as far as I can tell only exists to make otherwise “unsolvable” problems a kind of official solution. I personally feel like it is a bodge, and I would rather the correct solution for such a problem to be undefined.
100% with you. “Left to right” as far as I can tell only exists to make otherwise “unsolvable” problems a kind of official solution
It’s not a rule, it’s a convention, and it exists so as to avoid making mistakes with signs, mistakes you made in almost every example you gave where you disobeyed left to right.
It’s so we don’t have to spam brackets everywhere
9+2-1+6-4+7-3+5=
Becomes
((((((9+2)-1)+6)-4)+7)-3)+5=
That’s just clutter for no good reason when we can just say if it doesn’t have parentheses it’s left to right. Having a default evaluation order makes sense and means we only need parentheses when we want to deviate from the norm.
It’s so we don’t have to spam brackets everywhere
No it isn’t. The order of operations rules were around for several centuries before we even started using Brackets in Maths.
((((((9+2)-1)+6)-4)+7)-3)+5
It was literally never written like that
we only need parentheses when we want to deviate from the norm
That has always been the case
until the ambiguity is removed
There isn’t any ambiguity.
all those answers are correct
No, only 1 answer is correct, and all the others are wrong.
Until the author gives me clarity then that sentence has multiple meanings. With math
Maths isn’t English and doesn’t have multiple meanings. It has rules. Obey the rules and you always get the right answer.
it doesn’t click for people that the equation is incomplete.
It isn’t incomplete.
Can you explain how that is? Like with an example?
Math is exactly like English. It’s a language. It’s an abstraction to describe something. Ambiguity exists in math and in English. It impacts the validity of a statement. Hell the word statement is used in math and English for a reason.
Can you explain how that is? Like with an example?
I’m not sure what you’re asking about. Explain what with an example?
Math is exactly like English. It’s a language
No it isn’t. It’s a tool for calculating things, with syntax rules. We even have rules around how to say it when speaking.
It’s an abstraction to describe something
And that something is the Laws of the Universe. 1+1=2, F=ma, etc.
Hell the word statement is used in math and English for a reason
You won’t find the word “statement” used in Maths textbooks. I’m guessing you’re referring to Expressions.
Right to left:
6 * (4 / (2 * (3 / 9)))
Nope! 6 × 4 ÷ 2 × 3 ÷ 9 =4 right to left is 6 ÷ 9 x 3 ÷ 2 × 4 =4. You disobeyed the rule of Left Associativity, and your answer is wrong
Multiplication first: (6 * 4) / (2 * 3) / 9
Also nope. Multiplication first is 6 x 4 x 3 ÷ 2 ÷ 9 =4
Left first: (24 / 6) / 9
Still nope. 6 × 4 x 3 ÷ 2 ÷ 9 =4
Right side first: 24 / (6 / 9)
Still nope. 6 × 4 x 3 ÷ 9 ÷ 2 =4
And finally division first: 6 * (4 / 2) * (3 / 9)
And finally still nope. 6 ÷ 9 ÷ 2 x 4 x 3 =4
Hint: note that I never once added any brackets. You did, hence your multiple wrong answers.
It’s ambiguous which one of these is correct
No it isn’t. Only 4 is correct, as I have just shown repeatedly.
Hence the best method we have for “correct” is left to right
It’s because students don’t make mistakes with signs if you don’t change the order. I just showed you can still get the correct answer with different orders, but you have to make sure you obey Left Associativity at every step.
I stand corrected
I stand corrected
No, you weren’t. Most of their answers were wrong. You were right. See my reply. 4 is the only correct answer, and if you don’t get 4 then you did something wrong, as they did repeatedly (kept adding brackets and thus changing the Associativity).
Another person already replied using your equation, but I felt the need to reply with a simpler one as well that shows it:
9-1+3=?
Subtraction first:
8+3=11Addition first:
9-4=5Addition first: 9-4=5
Nope. Addition first is 9+3-1=12-1=11. You did 9-(1+3), incorrectly adding brackets and changing the answer (thus a wrong answer)
Oh my god now this is going to be Lemmy’s top thread for 6 months, isn’t it?
Btw, yeah I’m with you on this, you just need to know the priorities and you’re good, because the order doesn’t matter for operations with the same priority
Except it does matter. I left some examples for another post with multiplication and division, I’ll give you some addition and subtraction to see order matter with those operations as well.
Let’s take:
1 + 2 - 3 + 4Addition first:
(1 + 2) - (3 + 4)
3 - 7 = -4Subtraction first:
1 + (2 - 3) + 4
1 + (-1) + 4 = 4Right to left:
1 + (2 - (3 + 4))
1 + (2 - 7)
1 + (-5) = -4Left to right:
((1 + 2) - 3) + 4
(3 - 3) + 4 = 4Edit: You can argue that, for example, the addition first could be
(1 + 2) + (-3 + 4)in which case it does end up as 4, but in my opinion that’s another ambiguous case.Except it does matter
No it doesn’t. You disobeying the rules and getting lots of wrong answers in your examples doesn’t change that.
I left some examples for another post with multiplication and division
Which you did wrong.
I’ll give you some addition and subtraction to see order matter with those operations as well
And I’ll show you it doesn’t matter when you do it correctly
Subtraction first: 1 + (2 - 3) + 4 1 + (-1) + 4 = 4
Nope. Right answer for wrong reason - you only co-incidentally got the answer right. -3+1+2+4=-3+7=4
Right to left: 1 + (2 - (3 + 4)) 1 + (2 - 7) 1 + (-5) = -4
Nope. 4-3+2+1=1+2+1=3+1=4
Edit: You can argue that, for example, the addition first could be (1 + 2) + (-3 + 4)
Or you could just do it correctly in the first place, always obeying Left Associativity and never adding Brackets
in my opinion that’s another ambiguous case
There aren’t ANY ambiguous cases. In every case it’s equal to 4. If you didn’t get 4, then you made a mistake and got a wrong answer.
Oh, but of course the statement changes if you add parentheses. Basically, you’re changing the effective numbers that are being used, because the parentheses act as containers with a given value (you even showed the effective numbers in your examples).
Get this : + 1 - 1 + 1 - 1 + 1 - 1 + 1
You can change the result several times by choosing where you want to put the parentheses. However, the order of operations of same priority inside a container (parentheses) does not change the resulting value of the container.
In the example, there were no parentheses, so no ambiguity (there wouldn’t be any ambiguity with parentheses either, the correct way of calculating would just change), and I don’t think you can add “ambiguity” by adding parentheses — you’re just changing the effective expression to be evaluated.
By the way, this is the reason why I absolutely overuse parentheses in my engineering code. It can be redundant, but at least I am SURE that it is going to follow the order that I wanted.
Oh, but of course the statement changes if you add parentheses
It sure does, but they don’t seem to understand that.
So order of operations is hard?
Not for students it isn’t. Adults who’ve forgotten the rules on the other hand…
So if it’s not really an event
And it’s not really a math problem
What the hell is it??
Engagement bait
Entertainment.
The only thing that will remain on yt anyway after AI has taken over the content generation and we can trust no “creator” anymore.
Anyone on Facebook that attempts to answer this or engage within its comments has already failed the test.
Anyone on Facebook
that attempts to answer this or engage within its commentshas already failed the test.
Ah, yes. It’s only for genius.
Arguing about maths is like dancing to architecture.
Hey, some architecture is asking for it like Stonehenge
Every one of these only makes me say “wouldn’t it be great if we did everything with RPN”?
÷ could be a minus sign, see: https://en.wikipedia.org/wiki/Division_sign?wprov=sfla1
÷ could be a minus sign
No it couldn’t.
Did you check the reference? It says % can be used as a minus sign, not the obelus. Welcome to what happens when you’re next-door neighbour Joe Blow can edit Wikipedia.
