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I feel like I am getting trolled
Isn’t 17 the actual right answer?
Exactly
So it’s just an unfunny meme?
Not even a meme.
I think it’s meant to play with your expectations. Normally someone’s take being posted is to show them being confidently stupid, otherwise it isn’t as interesting and doesn’t go viral.However, because we’re primed to view it from that lens, we feel crazy to think we’re doing the math correctly and getting the “wrong answer” from what we assume is the “confident dipshit”.
There’s layers beyond the superficial.
I fell for it. It’s crazy to think how heavily I’ve been trained to believe everything I see is wrong in the most embarrassing and laughable way possible. That’s pretty depressing if you think about it.
Some people insist there’s no “correct” order for the basic arithmetic operations. And worse, some people insist the correct order is parenthesis first, then left to right.
Both of those sets of people are wrong.
Well, this is just a writing standard that is globally agreed on,
The writing rules are defined by humans not by natural force
(That one thing and another thing are two things, is a rule from nature, as comparison)Save yourself the trouble - Smartman Apps is a crank. They categorically will not comprehend the difference between the notation we made up and how numbers work. Dingus keeps saying ‘animals can count’ like that proves parentheses-first is completely different! from distribution.
Why’d Russel and Whitehead bother with the Principia Mathematica when they could just point to Clever Hans?
I mean, arithmetic order is just convention, not a mathematical truth. But that convention works in the way we know, yes, because that’s what’s… well… convention
Social conventions are real, well defined things. Some mathematicians like to pretend they aren’t, while using a truckload of them; that’s a hypocritical opinion.
That’s not to say you can’t change them. But all of basic arithmetic is a social convention, you can redefine the numbers and operations any time you want too.
Social conventions are real, well defined things
So are the laws of nature, that Maths arises from
Some mathematicians like to pretend they aren’t, while using a truckload of them; that’s a hypocritical opinion
No, you making false accusations against Mathematicians is a strawman
That’s not to say you can’t change them
You can change the conventions, you cannot change the rules
But all of basic arithmetic is a social convention
Nope, law of nature. Even several animals know how to count.
you can redefine the numbers and operations any time you want too
And you end up back where you started, since you can’t change the laws of nature
Hopefully you can see where their confusion might come from, though. PEMDAS is more P-E-MD-AS. If you have a bunch of unparenthesized addition and subtraction, left to right is correct. A lot of like, firstgrader math problems are just basic problems that are usually left to right (but should have some extras to highlight PEMDAS somewhere I’d hope).
So they’re mostly telling you they only remember as much math as a small child that barely passed math exercizes.
If you have a bunch of unparenthesized addition and subtraction, left to right is correct
If you have a bunch of unparenthesized addition and subtraction, left to right doesn’t matter.
1 + 2 + 3 = 3 + 2 + 1
If you have a bunch of unparenthesized addition and subtraction, left to right doesn’t matter.
Right, because 1-2-3=3-2-1.
Right, because 1-2-3=3-2-1
No, 1-2-3=-3-2+1. You changed the signs on the 1 and the 3.
Careful, you’ll summon Smartman Apps (with emojis) to insist mathematics has exactly one perfect unambiguous syntax, where 2*(1+3) is somehow different from 2(1+3), and also reverse Polish notation does-too have parentheses.
insist mathematics has exactly one perfect unambiguous syntax,
It sure does! 😂
2*(1+3) is somehow different from 2(1+3)
Yep, one is Multiplication - 2x3 - the other is The Distributive Law - (2x1+2x3) - both easily found in Maths textbooks
Fuck off.
I’m not humoring this again.
I’m not humoring this again
STILL can’t admit you’re wrong then 😂 I guess you never bothered looking in any Maths textbooks since last time then (or you did and don’t want to admit you found out you were wrong)
5 isn’t a valid function name, is obviously the right answer.
Damn, its always the simple math problem post with like, almost 700 comments lmao
Because of one troll harassing people to insist 2(8)2 is 256 and RPN has invisible brackets.
Presuming PEMDAS is our order of operations and the 5 next to the parentheses indicates multiplication…
2+5(8-5) -> 2+5(3) -> 2+15=17
Other than adding a multiplication indicator next to the left parentheses for clarification (I believe it’s * for programming and text chat purposes, a miniature “x” or dot for pen and paper/traditional calculators), this seems fine, yeah.
…I worry about how many people may not understand how to solve equations like these.
While I never failed a math class, I also never went past high school. When would your presumptions NOT be true?
Some forms of programming syntax, although there are the fringe cases where an equation (or function in programming) is represented by a symbol in conjunction with a parentheses input.
For example:
y(x) = 2*x+3
5+y(1) = 10, as 1 is substituted in for x in the prior equation.
And in some languages a number can be used as a name of a variable or a function, so it can be anything really
And in some languages a number can be used as a name of a variable or a function
Not in Maths it can’t
so it can be anything really
No, it can only be a Factorised Term, ab+ac=a(b+c). You also can’t call a function by any letter that you’ve used as a pronumeral
Wouldn’t we just assume function expressions are always “in parenthesis”? Then it’s just a substitution and no rules were changed.
Wouldn’t we just assume function expressions are always “in parenthesis”?
No, because factorised Terms also are, ab+ac=a(b+c).
But factorised terms are multiplications, so they’re still following the same rules: a(b+c) = a*(b+c)
Example: 2(3+5)=16, and also 2*3+2*5=16
But factorised terms are multiplications,
No, they’re Distribution done in the Brackets step, a(b+c)=(ab+ac), now solve (ab+ac)
a(b+c) = a*(b+c)
Nope! a(b+c)=(ab+ac). 1/a(b+c)=1/(ab+ac), but 1/ax(b+c)=(b+c)/a.
23+25=16
(2x3+2x5) actually, or you’ll get the wrong answer when it follows a Division sign. See previous point
1/a(b+c)=1/(ab+ac)
Nope, that’s wrong. See https://www.wolframalpha.com/input?i=10%2F2(2%2B3) for reference.
I prefer BM-DAS, no one’s out here doing exponents, and no one calls brackets “parentheses”…
The way I was taught growing up, brackets are [these]. Parenthesis are (these).
Yes, technically the latter are also brackets. But they can also be called parenthesis, whereas the former is exclusively a bracket. So we were taught to call them separate words to differentiate while doing equations.
The way I was taught growing up, brackets are [these]. Parenthesis are (these)
They’re all brackets. Parentheses is actually the part inside the ().
That’s not even an equation, just basic arithmetic
Technically not algebra, right? Algebra is where you move things around and solve for variables, and that kind of thing. This is just arithmetic.
Technically not algebra, right?
No, it actually is Algebra. The Distributive Law isn’t taught to students until they start on Algebra.
This is just arithmetic
There’s no a(b+c) in Arithmetic.
I don’t think you’re right. The wiki page literally uses a similar equation as an example of “elementary arithmetic.” It also uses a similar one, but with variables, as an example in “elementary algebra.” That implies that yes, this is arithmetic, and the introduction of variables is what makes it algebra.
It doesn’t matter what course finally teaches it to you. That could be just out of convenience, not by definition part of that domain. It’s been ages since I took it, though I could swear I learned this in pre-algebra (meaning before algebra), or earlier. I could be wrong on this though. Again, it’s been a very long time.
I don’t think you’re right
You don’t think Maths textbooks are right??
The wiki page
is full of disinformation. Note that they literally never cite any Maths textbooks
as an example of “elementary arithmetic.”
And whichever Joe Blow My Next Door Neighbour wrote that is wrong
as an example in “elementary algebra.”
Algebra isn’t taught until high school
That implies that yes, this is arithmetic,
No, anything with a(b+c) is Algebra, taught in Year 7
the introduction of variables is what makes it algebra
and the rules of Algebra, which includes a(b+c)=(ab+ac). There is no such rule in Arithmetic.
It doesn’t matter what course finally teaches it to you
It does if you’re going to argue over whether it’s Arithmetic or Algebra.
not by definition part of that domain
The Distributive Law is 100% part of Algebra. It’s one of the very first things taught (right after pronumerals and substitution).
It’s been ages since I took it
I teach it. We teach it to Year 7, at the start of Algebra
I’m sorry but isn’t this elementary school math?
In the rest of the world: yes.
In the US: I highly doubt it.
This is just basic math, if you can’t figure this out you’re probably 8 years old.
I think that ordering of calculation was taught around 5th grade back in my day (11yo)
Yeah, I’d say the same for central europe. 5th and 6th grade are when they throw a lot of math expression rules at you.
Thanks for confirming. I probably sounded too condescending but I wasn’t sure if it was a false memory.
I loved math as a kid though, so I ran through the curriculum as fast as I could to get to the good stuff. I think having older siblings helped - it gave me a preview of more interesting material.
Pemdas, parenthesis first, for a total of 3. Then multiplication, 15, then addition. 17. What’s hard about this?
Pemdas, parenthesis first, for a total of 3
Nope, a total of 15.
Then multiplication
There isn’t any Multiplication, only Addition and Brackets (and Subtraction inside Brackets).
And what do you do with the number inside the when you want to get rid of it?
And what do you do with the number inside the when you want to get rid of it?
You literally must distribute the coefficient before you can do anything with what is inside to remove Brackets, as per The Distributive Law, a(b+c)=(ab+ac), now you can work on getting rid of what is inside.
And what do you do with and and the b and then the a and the c? If you want to simplify the equation?
And what do you do with and and the b and then the a and the c? If you want to simplify the equation?
Add them, obviously 🙄
Guess I’ve been trolled.
And what do you do with and and the b and then the a and the c?
BTW, there’s no “the a and the b” and “the a and the c”, there’s ab and ac, which need to be added. If a=2, b=3, and c=4, we have 2(3+4)=(6+8)=14
That’s so evil and subtle. It took me multiple attempts to figure it out. You have to have quite the sharp eye to realize: no, you do not stop at calculating the numbers in parantesis first. You don’t add the resulting numbers, there is no +/- operator, so the number in parantesis is the power of the number before it. But wait! if You calculated 2+5 = 7 * 3 and hot 21, you are wrong. Remember that multiplication goes first, so it’s: 2+5(8-5) = 2+5*3=2+15=17
Remember that multiplication goes first
Remember Brackets are solved first - there is no Multiplication
so it’s: 2+5(8-5) = 2+5*3
No, so it’s: 2+5(8-5) = 2+(5x8-5x3), a(b+c)=(ab+ac).
Or it simply could be that I haven’t needed to concern myself with the order of operations more than a dozen times since high school. Even when working as a web coder it was so seldom necessary that I can’t recall a single example.
The US education system was still pretty decent when I was in middle and high school in the 1980s, so we definitely covered this in algebra.
I haven’t had to do this shit in 20 years since college. Literally nothing like this in my career path, I was shit at math in high school and college, so I didn’t even remember that there was a multiplication there since it isn’t explicit. Oh well.
that there was a multiplication there since it isn’t explicit
There isn’t a Multiplication there, only Addition and Brackets, and Subtraction inside Brackets. It’s never Multiplication unless there is a Multiplication sign.
Good for you. I don’t care.
2+5 is 8, 8-5 is 3. 8×3 is 24.
But I also haven’t done this kind of math since 4th grade so I’m not sure if the joke is that this is the real answer or the answer you get doing it wrong… 🤔
2+5 is 8
In which you just did Addition before Brackets, and is thus wrong
8-5 is 3
5(8-5) is 15
8×3
There is no 8x3. 2+5(8-5)=2+15=17
Obviously the answer is 2+x(y)
And even if you don’t simplify it to y the end result is the same
2+x(y-z) = 2+xy-xzI don’t know why, but this was intuitively my first approach. Eve though it’s much simpler than that.
To all the people yelling PEMDAS and BOMBDAS or whatever - languages other than English exist.
In French there’s no acronym. We just learn it. It’s not that hard.
It’s not like “PEMDAS” is easy to remember, as “Pemdas” as word does not exist.
We didn’t have anything to remember it by either, you just learn the order of operations and that’s it.
I don’t get why these kind of post crop up so often.
The answer to them doesn’t matter and these aren’t really math questions, because there is no context given. This is just endless discussions about different people having different assumptions on notation used there…
In real math, where the numbers mean something, good and consistent notation is important, but not necessary, because the order of operations or what those operations are exactly would be clear through the context of these formulas. Good notation just makes it easier to spot errors, work with formulas or to avoid confusion.
Here is what I would assume this formula could mean. Someone has 2 apples and 5 bags of apples that initially came with 8 apples each inside, but someone else ate 5 apples from each of these bags.
With this context it is pretty clear what the answer would be.
because there is no context given
None needed. Obey the rules of Maths and you get the correct answer.
the order of operations or what those operations are exactly would be clear through the context of these formulas
It’s clear to anyone who knows the rules of Maths.
Those aren’t ‘rules of maths’, because math would work with other orders of operations as well. They are conventions. Other cultures could have different conventions and it would work as well.
Those aren’t ‘rules of maths’,
Yes they are 😂
because math would work with other orders of operations as well.
There aren’t any “other” orders of operations.
They are conventions
Nope, rules of Maths
Other cultures could have different conventions and it would work as well
They do have other conventions, they do not have other rules. The rules of Maths are universal.
In mathematics and computer programming, the order of operations is a collection of conventions about which arithmetic operations to perform first in order to evaluate a given mathematical expression.
These conventions are formalized with a ranking of the operations. The rank of an operation is called its precedence, and an operation with a higher precedence is performed before operations with lower precedence. Calculators generally perform operations with the same precedence from left to right,[1] but some programming languages and calculators adopt different conventions.
https://en.wikipedia.org/wiki/Order_of_operations
With math, you can invent your own notation if you like. If it makes it easier to describe certain problem. This is done often. And if it makes sense, you can also change the order of operation. You can even introduce new operations.
The notation you learn in school is just a common one, but other notations are equally valid and can be useful.
Therefore this kind of question is not a pure math question, but rather it depends on what kind of conventions or notations people want to use.
The context is what allows the math question to have a single answer. The notation is just your chosen way towards that solution and to communicate the steps to that solution to others.
The rules of math itself are much more fundamental and they don’t care about how people decided to write formulas down.
isn’t a Maths textbook
In mathematics and computer programming, the order of operations is a collection of conventions
and rules 🙄 Haven’t even got past the first sentence you quoted and it’s already wrong
These conventions
Rules
but some programming languages and calculators
May disobey the rules and give wrong answers, like Texas Instruments calculators
With math, you can invent your own notation if you like
Yep, but you cannot invent your own rules 🙄
This is done often.
No it isn’t.
And if it makes sense, you can also change the order of operation
No you can’t, or you get wrong answers, like Texas Instruments calculators
The notation you learn in school is just a common one, but other notations are equally valid and can be useful
But the rules are universal. You seem to be confusing notation with the rules
Therefore this kind of question is not a pure math question
Yes it is
what kind of conventions or notations people want to use
We can see for ourselves quite clearly what notation they have used. There’s no mystery or debate about it
The context is what allows the math question to have a single answer
The rules of Maths is what gives it a single answer - that’s what they’re for! 😂
The rules of math itself are much more fundamental and they don’t care about how people decided to write formulas down.
Yep, one of which is The Distributive Law, a(b+c)=(ab+ac).
You poor thing…
You poor thing…
You don’t know what Maths textbooks say because you were too poor to go to school? I’m sorry to hear that
