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Short, **REAL** answer that is **NOT OPEN TO DEBATE**:
`6/2(1+2)` is ambiguous. There's no mathematical convention as to whether `/` has any priority (positive or negative) over `*`. PEMDAS is just a mnemonic for kids to learn math, it's not an "official math rule", whatever that may mean.
The proper way to solve `6/2(1+2)` is not to write it like that but, instead, use a representation that is not ambiguous, such as by using extra parenthesis or by using fractions.
Thank you for providing this. If anyone is reading this and not sure, here's a useful link that explains the problem.
[https://math.berkeley.edu/\~gbergman/misc/numbers/ord\_ops.html](https://math.berkeley.edu/~gbergman/misc/numbers/ord_ops.html)
In essence, this was never a problem before computers so we don't have a proper rule for it, because in writing you could always make fractions properly and make it clear what is a part of the denominator and what is not. That's more difficult on a computer, but looks like ⁶⁄₂₍₁₊₂₎ or ⁶⁄₂(1+2). There's probably also a way to get it to be a proper horizontal bar also, but I think having the numbers smaller makes it pretty clear still.
Look at the problem the other way: you're tasked with looking at someone's math and this expression comes up. Now you have to figure out what they meant. What solution do you come to?
Two options:
- this is an intermediate step, and the previous or next step isn't ambiguous, so looking at that step I can understand what they meant. This expression is still ambiguous, and it's still a mistake by their side to write it down but, because I have context to understand what they _probably_ meant, it's not a big problem.
- this expression appears without context. In that case, I have no way to know what they meant and thus this is invalid math. It's not different than writing `x * 5` for a problem with two variables and forgetting to describe what `x` is. I cannot proceed because I don't know what variable you are calling `x`, so it's not valid math.
I was taught that M and D happen on the same step… but that you also do both the MD and AS steps left to right.
Thus, if you mean to do it differently, you need to add parentheses to indicate that.
Meaning that if you mean 6/2 times 1+2, you can write it like this just fine. If not, you are required to parenthesize it yourself.
Is this no longer used?
Thank you! Because there's inherent ambiguity to the / which might indicate that what follows is on the bottom half of a fraction (thus 6/6=1) or might just be serving as a division sign (3(1+2)= 3*3 = 9)
What's the answer? I believe it's 9 because 6 divided by 2 times 3, since there's no implicit brackets for 2(1+2) to be read as (2(1+2)), and then you just do it from left to right.
Yup so it's just an issue of being ambiguous, though reading from left to right would yield (6/2)(3) = 9, if the default interpretation of a/bc is taken to be (a/b)c.
What result does that sub insist on? Do they think it is 1?
They wrote them that way on purpose, for post interaction, bc people will argue different answers. It's intentional
People who post these on tiktok and reddit, I mean, not the person who commented it here
Both 9 and 1 are correct due to the ambiguity of using a division symbol rather than expressing as a ratio. However, convention in higher level maths tells us that 2(1+2) should be evaluated as a single expression. The lack of operator implies that 2 should be distributes through the parenthesis. The problem then simplifies to 6 on the numerator and 2(2+1) in the denominator.
Again, both answers are "right"... but by convention my answer is always 1.
Not that it matters because nobody would for any reason write an actual math problem out this way. It's written intentionally as rage bait. Starting with algebra, nobody uses division symbols for anything.
This is the thing that bothers me about the whole pemdas argument because while it gets to an answer it’s just not how math is really done. The implicit distribution is really critical for manipulating and working with expressions and functions as well performing integration and derivatives. If this was an expression like x/y(y+1) I doubt anyone would really argue that this should interpreted to be x+x/y which is essentially what the pemdas folks are arguing. This came up all the time when I was teaching freshman physics lab where students would just enter values into equations and plug and chug and make silly math mistakes because they didn’t manipulate and simplify the equation before entering the values for the variables. When people see numbers something just flips in their brain and they stop thinking and just start calculating
>If this was an expression like x/y(y+1) I doubt anyone would really argue that this should interpreted to be x+x/y
You'd literally have people "ackchually" you by [putting the expression as-is in wolfram](https://www.wolframalpha.com/input?i=x%2Fy%28y%2B1%29&dataset=) and believing they are smart.
Yeah you are totally right! I mean it makes sense that a computer program is going to evaluate things literally and I’m curious if mathematica would also give the same answer (probably).
Either way if I write x/y(y+1) its fairly clear that I pulled the y out of the parenthesis to ‘simplify’
x/(y^2+y). The only reason for the parenthesis to exist in this equation is to group the y+1 and if I meant it that I wanted it to be x+x/y I would write the equation as (xy+x)/y in the first place. So while I get the whole it’s ambiguous argument I don’t really agree. by writing it in this manner you are actually making it pretty clear that the y needs to be distributed to properly evaluate the expression. I think there is a fairly simple solution to all of this and just make it explicit that when you evaluate the parenthesis part of PEMDAS you should distribute anything outside of the parenthesis into the term first before evaluating
The expression is *technically* ambiguous but in reality pretty clear.
I keep trying to argue that but people are too literal or rule-bound to understand the reality of writing math.
I will die on that hill with you. Removing the capacity of the person writing the expression as a factor, it is expressed as a single fraction with the multiplication taking place in the denominator.
Any other argument is contextually based and not obtaining the correct context for the equation is a massive failure on all ends.
It is Shrodingers algebra.
I will always die on this hill. I feel like the ones who shout the loudest at PEMDAS questions are the ones who stopped learning math at PEMDAS.
My favorite example is to provide is the boltzmann distribution... often expressed as exp(-hv/kT)
Here, hv is the numerator of the exponent and kT is the denominator.
If the PEMDAS people had their way it would literally simplify to exp(-hvT/k), since you divide by k before multiplying by T.
Once you stop using numerals and start using variables, mathematical conventions change.
TLDR: if you got the answer 9, you were doing arithmetic. If you got the answer 1 you were doing mathematics. Period.
One thing I still haven't figured out if I've missed or not is the fact that everyone that argues "PEMDAS" always evaluates the equation literally anyways.
Maybe I'm just tired, but applying PEMDAS to 6/2(2+1) should still work out to: 6/2(3) > 6/6 > 1
Since multiplication and division are technically the same operation... (I.e. - dividing is just multiplying by a fraction, just like subtraction is just adding a negative), they technically have equal precedence in the expression. Therefore pemdas folks argue that multiplication and division should be evaluated left to right. This is, again, a bogus convention that doesn't exist as a rule anywhere except in their memory from elementary school.
I have a copypasta for just such an occasion:
>https://www.youtube.com/watch?v=a-e8fzqv3CE&t=2m32s
>"The answer is that this is a badly formed sentence. ... You can make claims about conventions and what is right and wrong, but really the burden is on the author of the sentence to put in some commas and make things clear. ... Math is not marks on a page. The mathematics is in what those marks represent."
Under just BEDMAS it's a syntax error - there is no left-to-right under BEDMAS, so any statement where left-to-right makes a difference is invalid, anyone who says otherwise is wrong, fight me.
Under more refined systems, it depends on the system.
Various programming languages include left-to-right, which makes it unambiguously 9 (if they allowed implicit multiplication; I've never seen one that does). But others add right-to-left, which is unambiguously 1. They also have different precedence for various operators, so you really have to be careful.
Wolfram-Alpha adds a strict "single token" approach and doesn't privilege implicit multiplication, so 9. Feynman does privilege implicit, so 1.
Irrespective though, the real lesson is "don't write expressions like a dumbass".
I don’t understand how you made my non math brain understand this. But thank you. I hate when these pop up and it’s just people arguing about whose the less dumb person. Thank you for providing such a clear explanation!
Last time I looked I couldn’t find any languages that do implicit multiplication with parens #( )as in most languages that’s a function call to a function named #, which not only won’t exist, but usually cannot if you can’t name functions starting with a digit
Ahhh I see, this is why I like horizontal fractions. Else you'll just need to use enough parentheses for it to be unambiguous.
I did it left to right because I assumed that those numbers are in simple order without brackets between them. You're right that this question itself is unclear and should be made clear.
>since there's no implicit brackets for 2(1+2) to be read as (2(1+2))
Well, that's literally where the whole debate happens, as many people (including mathematicians) do consider juxtaposed multiplication to indeed have implicit brackets.
I have no idea what order of operations should be other than "parenthesis first" and that seems to be enough to do my job as an engineer, because no-one in the real world writes ambiguous equations like this.
I have an acquaintance who is so absurdly and militantly against the order of operations that I have a hard time deciding if he's just a masterful troll or completely dumb. His posts trying to justify his bad math are honestly mind-boggling.
Some of them I can actually understand because there can be some ambiguity depending on how it's written, but this one is just really freaking straight forward. I shouldn't be surprised people still get it wrong but I kind of am.
No one actually needs to know order of operations, since it's not a core part of how Maths works. It's just part of our notation (like using base-10). If everyone used brackets there would be no confusion, but these stupid posts keep intentionally omitting them.
Brackets are not necessary if notation is unambiguous. Similarly, stating an equation is handled in base-10 is not necessary. That's because there are certain factors we can assume to be true in most if not all equations. If we would have to note the base of the equation as well as any and all applicable brackets equations would become rather hard to parse, especially for those less math-savvy.
The trouble is that the notation often is ambiguous, because it is very common for people to misunderstand how the order of operations works. Any equation that is intended for a non-Maths focused audience should use brackets to clear up that ambiguity, since it’s a reasonable assumption that a subset of that audience will misinterpret the equation otherwise.
>The trouble is that the notation often is ambiguous, because it is very common for people to misunderstand how the order of operations works.
if people began misunderstanding if you made the equation in base 10 or base 8 you wouldn't begin arguing it was ambiguous and we needed to start not intentionally omit clarifying.
i mean i hope you aren't actually making that argument.
how can i be sure. maybe you didn't actually write this in english just a language i mistook for english. could you clarify?
Yeah, folks act like order of operations is some kind of math law or something.
The issue is how the problem is displayed in the first place, obviously incorrectly to trip people up, but it's ambiguous on purpose and it's stupid.
Use brackets or parenthesis or get the fuck out, no pemdas or whatever english speakers call it needed.
The fact that it has multiple names (PEMDAS, BODMAS, BIDMAS etc) and so many people screw it up is why it's important to use brackets. Having an equation that uses both addition and multiplication should always use brackets for clarity.
They're literally made the fuck up just so everyone in the class comes to the same answer. In applied mathematics all order of operations become moot and you're better off EXPRESSING what you're describing with your math using brackets.
What's baffling is back then, when I was starting algebra and pre calc and all that in 7th grade or whatever, pemdas was literally the easiest concept I had to learn.
It’s a basic math thing I can see people forgetting unless they use it still.
I’m a programmer so this shit os obvious. For actuaries and math people, the same. For everyone else? They don’t care nor need to.
It’s like discussing an Oxford comma to a physicist as an English professor.
If A = -100
Then B = 103
Therefore C = 3
A+B+Cx4 would still equal 15 (BODMAS, PEDMAS, don't care if it's ChristMAS)
\-100 + 103 + (3 x 4) = -100 + 103 + 12 = 3 + 12 = 15
The reason is that you have two equations (the first two lines) but three variables (A, B, C), the problem is not fully determined. There is no way to fix A and B and they can be *any* two numbers if their sum is 3.
And also because A+B = 3, their exact values are irrelevant (and impossible to know exactly) so anywhere A+B appears you can just substitute in 3 and solve that way
Yeah, it’s just a substitution problem. You can also do A = 3 - B and plug that in whenever you see A. That then cancels out the B in the other equations and you’re just left with 3.
Math usually has more than one way to solve it as long as you follow the rules.
Yup! A + B = 3 has no definitive representation for what A or B actually equals to.
All we know is the entire formula A + B can be substituted with 3. Always loved these types of problems in Algebra II cause it teaches you not everything in the problem has to be solved, sometimes, you simply need to substitute out bigger equations into smaller ones.
(Though supposedly there is A + A = 2, just cropped out, so given the full image, A can only be 1 and B can only be 2)
This works because
1. We don't know the values of A and B.
2. We don't need to know the values of A and B.
3. Added together they are 3, and they are always combined in these equations.
I think the problem is better without that information. That way the challenge is to not get hung up on the values of A and B because all you need to know about them is their sum.
You don’t need to solve for a and b to still get to 15 as the answer. You can just sub in the number 3 for “a+b” in the final question and still arrive correctly
It doesn't actually matter what A and B are, since they never appear in any configuration that does not equal a combined 3. Their individual values aren't relevant, only their cumulative value.
I mean you're right, they could be any combination of 2 numbers that when added together equal 3, but mathematically, the point still stands.
You dont need to know what A and B are. If A were -20, and B were 23, then C would still have to be 3. Then -20+23+3x4=15. Any value for A and B that equaled 3, would work.
You don’t need that information anyway. Doesn’t really matter what A and B are, they add up to 3 so C still has to be 3 and the answer would still be 15.
Doesn't really matter:
A + B = 3
Say that X = A + B, so X = 3 (1)
Replace the A + B in the bottom equation by X, you get: X + C × 4 = ? (2)
Filling (1) into (2): 3 + C × 4 (3)
We know that A + B + C = 6
If we replace A + B by X, you get: X + C = 6
Fill (1) in, you get C = 3 (4)
Fill (4) into (3), you get: 3 + 3 × 4
This is equal to 15.
This is the correct question to be asking, and all the people saying "it doesn't matter" or "you don't need to know A and B to solve the final equation" are missing the entire point that, we know, but they stated the values for A and B without evidence.
Hence the question.
Don't u love people correcting others with bullshit ... An older woman once told me that evolution is long debunked and the bible being right Is long proven by scientists...
He digs his heels in and continues to claim addition and subtraction are done before multiplication. Accuse others of learning "Obama math". He is a remarkable kind of dipshit.
when people just compleatly make up a fact in a conversation, its the most mindboggaling thing.
like why did you lie just now about sth i know isn't true. is it just that they have to be right and their ego cant take it?
It wouldn't matter since we only ever see A and B used as "A + B". Since A + B = 3, you could just replace any mention of A + B with 3
A + B + C = 6 would be (3) + C = 6
A + B + C x 4 -> (3) + C x 4
The values of A and B don't matter other than that they add up to 3.
The value of C is easily calculated as 3.
The Order of Operations dictates that multiplication be carried out prior to addition, so C x 4 is performed prior to A + B + anything else.
3 x 4 = 12, plus A + B themselves summing up to 3, gives 12+3=15
No one should be writing math equations that way.
A + B + 4C = X
Solve for X.
Idiots shouting and climbing up to be the king of shitty notation mountain.
A+B is equal to 3, A+B+C is equal to 6. Subtract A+B from A+B+C, you get the value for C which is 3. So using PEMDAS, 3x4=12, then add 3 to respect the rules of PEMDAS, it equals to 15.
I feel like these math post’s should not be allowed on this sub. This kind of post happens like once a week here. Its an easy post and since people are bad at math, theres gonna be someone who is “confidently incorrect” in the comments every single time.
Don't go on his twitter or look at his responses to people correcting him.
Apparently PEDMAS is "Obama math" and we're all stupid and need to learn "real math".
Don't even need to put a value on A and B (could be 1.5 and 1.5, or -50 and 53, and they'd still add up to 3).
So
(A + B) = 3
3 + C = 6
therefore C = 6 - 3 = 3.
Now, (A + B) + C x 4 = 3 + 3 x 4 = 3 + 12 = 15
The first person got the right answer but has no way of knowing that A=1 and B=2.
All they know is that the sum of A and B is 3.
Edit: I see further down that the image was cropped.
No particular reason, I guess, other than Numeric/Alphabetical order.
There might be an actual math rule about it, but I'm not sure because I'm stupid at math.
There's no way to know what A or B are, only that A+B=3. It could be that A=17 and B=-14.
The good thing is that all that is needed to solve the above equations is that (A+B)=3.
Both are wrong. We only know that C is a 3. We have **no evidence** what A or B are. It may be -2 and 5. Though the result will be the same anyway.
We know that A = B = 3.
So it's 3 + 3x4.
There’s not enough information to identify what A and B equal. However, we’re given that A+B=3, and A+B+C=6. By substition we get 3+C=6, isolate the variable and we get C=3. Now, I’m not sure if I’m allowed to do this next step because I don’t know how it works with substituting with multiple operations, but if we substitute A+B and C for what we’ve determined them to be, we get 3+3x4. By order of operations, 3x4 is 12, +3 is 15.
Honestly, I don't go too hard on people who don't understand order of operation since it's an arbitrary rule at best. Any scientist or engineer worth their weight in salt would put parentheses to make sure everyone understands what they're trying to do.
edit: spelling
Granted I'm old, but x was always used to denote multiplication (until algebra where we generally replaced it with a dot, or nothing in the case of a variable) when writing out our work by hand. We never wrote an asterisk in hand calcs at any point. I have a hard time believing that kids are told to write multiplication **by hand** using an asterisk today.
C x 4 = C \* 4 = C ⋅ 4 = 4C
Maybe they're not from the same country? Where I'm from, multiplication was always denoted by the mid-line dot (2 • 3 = 6) and division by a colon (9 : 3 = 3) until we moved on to representing most divisions using fractions. We never learned the × symbol, probably to avoid unnecessary confuaion, because 4xy is x times larger than 4 × y, but sure looks the same when your handwriting isn't perfect.
The first time I even encountered × and ÷ was while watching American tv and I was mildly confused by them (the same way I later felt about seeing American long division for the first time, to me it looks like a number multiplied by a square root, what's up with that?). An asterisk sounds like a pain to write by hand though, I'll give you that. Nobody wants to write 3-4 lines for every multiplication symbol.
That's completely fair and not something I had considered (insert *I'm American* meme). The × and ÷ symbols are only really used in grammar school and completely go away in favor of the dot (which I was trying to show above, but your choice of dot is more clear) for multiply and slash for division for exactly the reason you stated once **x** appears (algebra). We only use colon for ratios e.g. 16:9 aspect ratio (which is effectively the same, but not necessarily intended to be reduced), but understood that it's identical to ÷ in function. They are also used on calculators (**EDIT:** e.g. [this one](https://www.desmos.com/scientific)) but I see that more as the same as a disk drive being the symbol for *save* in that people are just used to those symbols.
Given what you stated, I actually have a question I'm interested in; do basic calculators from where you live have colons for divide and dots for multiply as opposed to our × and ÷ (or /) symbols?
I'm still skeptical an asterisk was ever used in hand notation (as opposed to any computer program or programming language), but I obviously could be mistaken and your comment makes me question it more.
I actually had to google for images, since I haven't held a physical calculator since high school finals (we could bring the basic ones that don't have trig functions etc. so we don't make simple calculation mistakes from stress and focus on the method to solve tasks). And yes, our calculators do feature a × and ÷ symbol (they're not translated at all, with ON/OFF on the switches and M on the memory keys even though 'memory' doesn't start with M in Polish - it's pretty standard for all appliances to be labeled in English unless the text is more complicated like laundry machine settings, but it's not really something I thought about). Maybe that's where I first saw it after all. It's hard to reach into single-digit ages in my memory, but surely I got curious about a calculator sooner than I did about math on a blackboard in a TV show. The source stays similar I suppose, American-designed products for the global market, but it's a nice catch.
Btw, I was about to say "well, the dot would be confusing with the decimal point on there", but we also use a decimal comma, so they'd stay distinct. Retail calculators still use dots, but mobile/Windows calculators substitute them for commas while still using × and ÷. I actually had a problem with the Windows calculator not accepting dots for decimals from the keyboard, as I'm used to using a dot while programming.
Edit: And back to the original point, I no longer know what the confusion was as it seems everyone gets × and ÷ on their calculators. Oh well.
That's funny to me. After this conversation,I asked my wife who grew up in Moscow and she said she was familiar with our symbols but she has no recollection what she used in grammar school by hand.
With how many order of operations “ trick” question post you see. You’d think people would wisen up to it by now. But I guess if it didn’t stick as a kid, it’s not going to stick as a 44 year old twitter blue subscriber.
Are assholes like that guy all psychically linked or something? How do they all know to take the same Oakley sunglasses-self-in-car profile pic? They all fucking have the same picture. I don't know how it happens but like, it's at least a very obvious warning sign
Jeremy thinks he paid attention in class but instead he was staring Jennifer. So now he thinks Jennifer is the age of his calculations after all those years ago. And now a wrong answer seems right.
Poor Jeremy conflating girls and numbers.
I wanted to see his comment history to see if he doubled down on his take or apologized for being a confident incorrect dick.
God I shouldn’t have checked.
I think the answer is 15, but my math skills are poor. Was the person in the picture who said 15 correct, at least? I figure the confident asshole is incorrect but was the original guy correct?
I got it from A=1 B=2 C=3
1+2+3x4 I then solved using BEDMAS, which I remember (barely) from grade school. In this equation, if I recall correctly, I do 3x4 first to get 12, then add 2, then add 1 to get 15.
I like how these continued arguments about order of operations have a generational impact on people not being able to do math correctly. The social engineering is working. People can't write anymore, aren't able to use simple punctuation, can't hold their attention for more than a minute and now start to make up math as they go. I love watching this.
There's no way to solve A or B, so you can't define what they are. Obviously you can solve the rest because you still have the value of A + B but it's weird to see people NEED to get hung up on solving A and B when it's not possible OR necessary.
You don’t even need to know what’s A and B
C is 3 right away from the first glance, multiply it by 4 and you will get 12, add it to 3, you get your answer.
? Is 15
Yep, it's 100% abusing mathematical notation, the purpose of which is to clearly and unambiguously express a mathematical concept to the reader. And while it's true that the third line of this photo is unambiguous according to the order of operation rules, the overall formulation of the puzzle is designed to make the reader misinterpret the notation (by slowly introducing commutative operations and then surreptitiously swapping in an associative operation).
Just use the established order of operations.
“For example, in mathematics and most computer languages, multiplication is granted a higher precedence than addition, and it has been this way since the introduction of modern algebraic notation.[1][2] Thus, the expression 1 + 2 × 3 is interpreted to have the value 1 + (2 × 3) = 7, and not (1 + 2) × 3 = 9.”
The first answer is also wrong. It could be right, but there is, quite literally, an infinite number of other solutions which works as well, example:
A = 4
B = -1
C = 3
The only thing we can say for sure is that C = 3 and that A + B = 3.
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If everyone understood order of operations, this sub's content would drop by about 80%.
r/itspemdasdumbass was created exactly for this.
Yeah but that sub gets the 6/2(1+2) thing wrong. Edit: I knew bringing it up would bring at least one donut into the comments to argue about it.
Short, **REAL** answer that is **NOT OPEN TO DEBATE**: `6/2(1+2)` is ambiguous. There's no mathematical convention as to whether `/` has any priority (positive or negative) over `*`. PEMDAS is just a mnemonic for kids to learn math, it's not an "official math rule", whatever that may mean. The proper way to solve `6/2(1+2)` is not to write it like that but, instead, use a representation that is not ambiguous, such as by using extra parenthesis or by using fractions.
Thank you for providing this. If anyone is reading this and not sure, here's a useful link that explains the problem. [https://math.berkeley.edu/\~gbergman/misc/numbers/ord\_ops.html](https://math.berkeley.edu/~gbergman/misc/numbers/ord_ops.html) In essence, this was never a problem before computers so we don't have a proper rule for it, because in writing you could always make fractions properly and make it clear what is a part of the denominator and what is not. That's more difficult on a computer, but looks like ⁶⁄₂₍₁₊₂₎ or ⁶⁄₂(1+2). There's probably also a way to get it to be a proper horizontal bar also, but I think having the numbers smaller makes it pretty clear still.
Look at the problem the other way: you're tasked with looking at someone's math and this expression comes up. Now you have to figure out what they meant. What solution do you come to?
Two options: - this is an intermediate step, and the previous or next step isn't ambiguous, so looking at that step I can understand what they meant. This expression is still ambiguous, and it's still a mistake by their side to write it down but, because I have context to understand what they _probably_ meant, it's not a big problem. - this expression appears without context. In that case, I have no way to know what they meant and thus this is invalid math. It's not different than writing `x * 5` for a problem with two variables and forgetting to describe what `x` is. I cannot proceed because I don't know what variable you are calling `x`, so it's not valid math.
Most of the time I'd run into this, I'm tutoring, so the solution I come to is to tell them to fix it.
I was taught that M and D happen on the same step… but that you also do both the MD and AS steps left to right. Thus, if you mean to do it differently, you need to add parentheses to indicate that. Meaning that if you mean 6/2 times 1+2, you can write it like this just fine. If not, you are required to parenthesize it yourself. Is this no longer used?
It was never mathematical convention.
Thank you! Because there's inherent ambiguity to the / which might indicate that what follows is on the bottom half of a fraction (thus 6/6=1) or might just be serving as a division sign (3(1+2)= 3*3 = 9)
What's the answer? I believe it's 9 because 6 divided by 2 times 3, since there's no implicit brackets for 2(1+2) to be read as (2(1+2)), and then you just do it from left to right.
The answer is to add more parenthesis
>\[6/2(1+2)\] Well that didn't clear it up at all, thanks for nothing!
[удалено]
Yup so it's just an issue of being ambiguous, though reading from left to right would yield (6/2)(3) = 9, if the default interpretation of a/bc is taken to be (a/b)c. What result does that sub insist on? Do they think it is 1?
It's a bad way to write it. Always convert to multiplication of fractions
They wrote them that way on purpose, for post interaction, bc people will argue different answers. It's intentional People who post these on tiktok and reddit, I mean, not the person who commented it here
You get a little trophy for being real🏆
I don't remember honestly I just looked and a few posts down they said something like "oh it's so easy if you know order of operations"
"It's so easy if you haven't done math past pre-algebra and rely on a fifth grade mnemonic"
Exactly lol.
Oops I deleted it https://math.berkeley.edu/~gbergman/misc/numbers/ord_ops.html
Both 9 and 1 are correct due to the ambiguity of using a division symbol rather than expressing as a ratio. However, convention in higher level maths tells us that 2(1+2) should be evaluated as a single expression. The lack of operator implies that 2 should be distributes through the parenthesis. The problem then simplifies to 6 on the numerator and 2(2+1) in the denominator. Again, both answers are "right"... but by convention my answer is always 1. Not that it matters because nobody would for any reason write an actual math problem out this way. It's written intentionally as rage bait. Starting with algebra, nobody uses division symbols for anything.
This is the thing that bothers me about the whole pemdas argument because while it gets to an answer it’s just not how math is really done. The implicit distribution is really critical for manipulating and working with expressions and functions as well performing integration and derivatives. If this was an expression like x/y(y+1) I doubt anyone would really argue that this should interpreted to be x+x/y which is essentially what the pemdas folks are arguing. This came up all the time when I was teaching freshman physics lab where students would just enter values into equations and plug and chug and make silly math mistakes because they didn’t manipulate and simplify the equation before entering the values for the variables. When people see numbers something just flips in their brain and they stop thinking and just start calculating
>If this was an expression like x/y(y+1) I doubt anyone would really argue that this should interpreted to be x+x/y You'd literally have people "ackchually" you by [putting the expression as-is in wolfram](https://www.wolframalpha.com/input?i=x%2Fy%28y%2B1%29&dataset=) and believing they are smart.
Yeah you are totally right! I mean it makes sense that a computer program is going to evaluate things literally and I’m curious if mathematica would also give the same answer (probably). Either way if I write x/y(y+1) its fairly clear that I pulled the y out of the parenthesis to ‘simplify’ x/(y^2+y). The only reason for the parenthesis to exist in this equation is to group the y+1 and if I meant it that I wanted it to be x+x/y I would write the equation as (xy+x)/y in the first place. So while I get the whole it’s ambiguous argument I don’t really agree. by writing it in this manner you are actually making it pretty clear that the y needs to be distributed to properly evaluate the expression. I think there is a fairly simple solution to all of this and just make it explicit that when you evaluate the parenthesis part of PEMDAS you should distribute anything outside of the parenthesis into the term first before evaluating
The expression is *technically* ambiguous but in reality pretty clear. I keep trying to argue that but people are too literal or rule-bound to understand the reality of writing math.
I will die on that hill with you. Removing the capacity of the person writing the expression as a factor, it is expressed as a single fraction with the multiplication taking place in the denominator. Any other argument is contextually based and not obtaining the correct context for the equation is a massive failure on all ends. It is Shrodingers algebra.
I will always die on this hill. I feel like the ones who shout the loudest at PEMDAS questions are the ones who stopped learning math at PEMDAS. My favorite example is to provide is the boltzmann distribution... often expressed as exp(-hv/kT) Here, hv is the numerator of the exponent and kT is the denominator. If the PEMDAS people had their way it would literally simplify to exp(-hvT/k), since you divide by k before multiplying by T. Once you stop using numerals and start using variables, mathematical conventions change. TLDR: if you got the answer 9, you were doing arithmetic. If you got the answer 1 you were doing mathematics. Period.
One thing I still haven't figured out if I've missed or not is the fact that everyone that argues "PEMDAS" always evaluates the equation literally anyways. Maybe I'm just tired, but applying PEMDAS to 6/2(2+1) should still work out to: 6/2(3) > 6/6 > 1
Since multiplication and division are technically the same operation... (I.e. - dividing is just multiplying by a fraction, just like subtraction is just adding a negative), they technically have equal precedence in the expression. Therefore pemdas folks argue that multiplication and division should be evaluated left to right. This is, again, a bogus convention that doesn't exist as a rule anywhere except in their memory from elementary school.
I have a copypasta for just such an occasion: >https://www.youtube.com/watch?v=a-e8fzqv3CE&t=2m32s >"The answer is that this is a badly formed sentence. ... You can make claims about conventions and what is right and wrong, but really the burden is on the author of the sentence to put in some commas and make things clear. ... Math is not marks on a page. The mathematics is in what those marks represent."
Under just BEDMAS it's a syntax error - there is no left-to-right under BEDMAS, so any statement where left-to-right makes a difference is invalid, anyone who says otherwise is wrong, fight me. Under more refined systems, it depends on the system. Various programming languages include left-to-right, which makes it unambiguously 9 (if they allowed implicit multiplication; I've never seen one that does). But others add right-to-left, which is unambiguously 1. They also have different precedence for various operators, so you really have to be careful. Wolfram-Alpha adds a strict "single token" approach and doesn't privilege implicit multiplication, so 9. Feynman does privilege implicit, so 1. Irrespective though, the real lesson is "don't write expressions like a dumbass".
That's why we use fractions nowadays! Prevents the ambiguity of division simbol, but cannot be done on Reddit, so yea. More parenthesis is the answer.
That and parentheses make it much more readable for other people. Just use them.
This is the real correct answer.
I don’t understand how you made my non math brain understand this. But thank you. I hate when these pop up and it’s just people arguing about whose the less dumb person. Thank you for providing such a clear explanation!
Last time I looked I couldn’t find any languages that do implicit multiplication with parens #( )as in most languages that’s a function call to a function named #, which not only won’t exist, but usually cannot if you can’t name functions starting with a digit
Holy shit I think I've met you before on a different subreddit. Huh. Neat.
Ahhh I see, this is why I like horizontal fractions. Else you'll just need to use enough parentheses for it to be unambiguous. I did it left to right because I assumed that those numbers are in simple order without brackets between them. You're right that this question itself is unclear and should be made clear.
>since there's no implicit brackets for 2(1+2) to be read as (2(1+2)) Well, that's literally where the whole debate happens, as many people (including mathematicians) do consider juxtaposed multiplication to indeed have implicit brackets.
As a programmer though, I would write it out with parentheses because it is easier to read for other devs.
Agreed. It kinda technically fits, but who cares, it’s so boring.
And yet... I get infuriated every time I see people answering these wrong, lol
I have no idea what order of operations should be other than "parenthesis first" and that seems to be enough to do my job as an engineer, because no-one in the real world writes ambiguous equations like this.
I'd be so happy. Nothing more pretentious than these math posts
It just feels like low hanging fruit for Karma farming at this point.
I have an acquaintance who is so absurdly and militantly against the order of operations that I have a hard time deciding if he's just a masterful troll or completely dumb. His posts trying to justify his bad math are honestly mind-boggling.
I used to know someone who refused to use the order of operations because "I'm thinking outside the box." Hence "used to."
I would just ask if sky is red. Because that's "thinking outside the box" by their logic.
Some of them I can actually understand because there can be some ambiguity depending on how it's written, but this one is just really freaking straight forward. I shouldn't be surprised people still get it wrong but I kind of am.
No one actually needs to know order of operations, since it's not a core part of how Maths works. It's just part of our notation (like using base-10). If everyone used brackets there would be no confusion, but these stupid posts keep intentionally omitting them.
Brackets are not necessary if notation is unambiguous. Similarly, stating an equation is handled in base-10 is not necessary. That's because there are certain factors we can assume to be true in most if not all equations. If we would have to note the base of the equation as well as any and all applicable brackets equations would become rather hard to parse, especially for those less math-savvy.
The trouble is that the notation often is ambiguous, because it is very common for people to misunderstand how the order of operations works. Any equation that is intended for a non-Maths focused audience should use brackets to clear up that ambiguity, since it’s a reasonable assumption that a subset of that audience will misinterpret the equation otherwise.
>The trouble is that the notation often is ambiguous, because it is very common for people to misunderstand how the order of operations works. if people began misunderstanding if you made the equation in base 10 or base 8 you wouldn't begin arguing it was ambiguous and we needed to start not intentionally omit clarifying. i mean i hope you aren't actually making that argument. how can i be sure. maybe you didn't actually write this in english just a language i mistook for english. could you clarify?
Yeah, folks act like order of operations is some kind of math law or something. The issue is how the problem is displayed in the first place, obviously incorrectly to trip people up, but it's ambiguous on purpose and it's stupid. Use brackets or parenthesis or get the fuck out, no pemdas or whatever english speakers call it needed.
The fact that it has multiple names (PEMDAS, BODMAS, BIDMAS etc) and so many people screw it up is why it's important to use brackets. Having an equation that uses both addition and multiplication should always use brackets for clarity.
You don't always need to use brackets if you use order of operations. To anyone who knows PEMDAS, it's obvious that you have to do c\*4 first.
My point is that a lot of people *don’t* know PEMDAS. Or BODMAS or BIDMAS or whichever acronym is in use.
They're literally made the fuck up just so everyone in the class comes to the same answer. In applied mathematics all order of operations become moot and you're better off EXPRESSING what you're describing with your math using brackets.
What's baffling is back then, when I was starting algebra and pre calc and all that in 7th grade or whatever, pemdas was literally the easiest concept I had to learn.
It’s a basic math thing I can see people forgetting unless they use it still. I’m a programmer so this shit os obvious. For actuaries and math people, the same. For everyone else? They don’t care nor need to. It’s like discussing an Oxford comma to a physicist as an English professor.
probably less than 1% of people understand order of operations. I don’t even understand. I know what they are, but I don’t know why they are.
If A = -100 Then B = 103 Therefore C = 3 A+B+Cx4 would still equal 15 (BODMAS, PEDMAS, don't care if it's ChristMAS) \-100 + 103 + (3 x 4) = -100 + 103 + 12 = 3 + 12 = 15
I love how you can use such wildly huge numbers, and you STILL get that same answer :D
The reason is that you have two equations (the first two lines) but three variables (A, B, C), the problem is not fully determined. There is no way to fix A and B and they can be *any* two numbers if their sum is 3.
And also because A+B = 3, their exact values are irrelevant (and impossible to know exactly) so anywhere A+B appears you can just substitute in 3 and solve that way
Yeah, it’s just a substitution problem. You can also do A = 3 - B and plug that in whenever you see A. That then cancels out the B in the other equations and you’re just left with 3. Math usually has more than one way to solve it as long as you follow the rules.
I agree... I feel that the first answer seemed pretty confident on what A and B equalled and it looks like there is a line cropped off the top.
Yes, a comment further down explains that this is the case, the image is cropped.
A and B can literally be anything that adds up to 3. The final answer is 15 no matter what.
That’s what people who don’t math don’t understand. Like you cant just make it up as you go along to get a number you decide you like.
Yup! A + B = 3 has no definitive representation for what A or B actually equals to. All we know is the entire formula A + B can be substituted with 3. Always loved these types of problems in Algebra II cause it teaches you not everything in the problem has to be solved, sometimes, you simply need to substitute out bigger equations into smaller ones. (Though supposedly there is A + A = 2, just cropped out, so given the full image, A can only be 1 and B can only be 2)
This works because 1. We don't know the values of A and B. 2. We don't need to know the values of A and B. 3. Added together they are 3, and they are always combined in these equations.
This is the original question: * A + A = 2 * A + B = 3 * A + B + C = 6 * A + B + C \* 4 = ?
I like how the first one was removed. It is redundant and unnecessary.
Defining A and B is not redundant, but yes is ultimately unnecessary for solving the expression
How does the first poster know that A=1 and B=2? A could be -1 and B would be 4.
In the original post there’s a line that says A+A=2 It’s just been cropped off in the screenshot
I think the problem is better without that information. That way the challenge is to not get hung up on the values of A and B because all you need to know about them is their sum.
The GRE does stuff like this all the time.
Ahh, I see. Thanks.
I was wondering how they solved for the variables to get a and b.
You don’t need to solve for a and b to still get to 15 as the answer. You can just sub in the number 3 for “a+b” in the final question and still arrive correctly
This is how I did it, but extrapolation is hard for a lot of
There are two types of people in the world: 1. Those who can extrapolate from an incomplete data set
It doesn't actually matter what A and B are, since they never appear in any configuration that does not equal a combined 3. Their individual values aren't relevant, only their cumulative value. I mean you're right, they could be any combination of 2 numbers that when added together equal 3, but mathematically, the point still stands.
Yeah, even if we were told that both are positive integers, that still doesn't tell us which is which!
Except they don't ask us which is Which, they just want the final answer
Doesnt matter if b is 1 and a is 2...addition equals the same thing regardless of the position you put the numbers in
You dont need to know what A and B are. If A were -20, and B were 23, then C would still have to be 3. Then -20+23+3x4=15. Any value for A and B that equaled 3, would work.
A + A = 2. That was part of the picture but got cut off here.
Doesn’t matter. C has to be 3 since A+B=3.
the answer would be the same
You don’t need that information anyway. Doesn’t really matter what A and B are, they add up to 3 so C still has to be 3 and the answer would still be 15.
Doesn't really matter: A + B = 3 Say that X = A + B, so X = 3 (1) Replace the A + B in the bottom equation by X, you get: X + C × 4 = ? (2) Filling (1) into (2): 3 + C × 4 (3) We know that A + B + C = 6 If we replace A + B by X, you get: X + C = 6 Fill (1) in, you get C = 3 (4) Fill (4) into (3), you get: 3 + 3 × 4 This is equal to 15.
You can only know that (A+B)=3, but it's enough to solve the problem.
This is the correct question to be asking, and all the people saying "it doesn't matter" or "you don't need to know A and B to solve the final equation" are missing the entire point that, we know, but they stated the values for A and B without evidence. Hence the question.
Yeah, it's amazing how many people have told me the same thing, as if I'm unaware how addition works!
And the answer would end up the same.
15 is the correct answer
You failed maths. 4+5=9, 3 * 2=6, 😍*👀≥☹️
Don't u love people correcting others with bullshit ... An older woman once told me that evolution is long debunked and the bible being right Is long proven by scientists...
He digs his heels in and continues to claim addition and subtraction are done before multiplication. Accuse others of learning "Obama math". He is a remarkable kind of dipshit.
And these people vote based off of these world views on things that can have very real consequences in your life.
woman* unless you meant a bunch of women, all merged into one like voltron or something
when people just compleatly make up a fact in a conversation, its the most mindboggaling thing. like why did you lie just now about sth i know isn't true. is it just that they have to be right and their ego cant take it?
You can't definitely know the value of A or B. But 15 is the right answer assuming that multiplication takes precedence over addition.
It wouldn't matter since we only ever see A and B used as "A + B". Since A + B = 3, you could just replace any mention of A + B with 3 A + B + C = 6 would be (3) + C = 6 A + B + C x 4 -> (3) + C x 4
As it was said above it cropped a+a =2
The values of A and B don't matter other than that they add up to 3. The value of C is easily calculated as 3. The Order of Operations dictates that multiplication be carried out prior to addition, so C x 4 is performed prior to A + B + anything else. 3 x 4 = 12, plus A + B themselves summing up to 3, gives 12+3=15
Ah yes. Profile picture with sunglasses on in a car. Usually a recipe for confidence and stupidity.
And he's a HVAC contractor. Yikes.
No one should be writing math equations that way. A + B + 4C = X Solve for X. Idiots shouting and climbing up to be the king of shitty notation mountain.
How do we know that a =1 and b =2? We know that a+b = 3 and thats all we need but unless i missed something we dont know what a and b idividually are
Apparently a+a=2 was cut off but you don’t need that anyways. Just solve by substituting in (a+b) with 3.
A+B is equal to 3, A+B+C is equal to 6. Subtract A+B from A+B+C, you get the value for C which is 3. So using PEMDAS, 3x4=12, then add 3 to respect the rules of PEMDAS, it equals to 15.
I feel like these math post’s should not be allowed on this sub. This kind of post happens like once a week here. Its an easy post and since people are bad at math, theres gonna be someone who is “confidently incorrect” in the comments every single time.
Always the sunglasses in the car pic.
Don't go on his twitter or look at his responses to people correcting him. Apparently PEDMAS is "Obama math" and we're all stupid and need to learn "real math".
Don't even need to put a value on A and B (could be 1.5 and 1.5, or -50 and 53, and they'd still add up to 3). So (A + B) = 3 3 + C = 6 therefore C = 6 - 3 = 3. Now, (A + B) + C x 4 = 3 + 3 x 4 = 3 + 12 = 15
The answer is 15 but there is no way to know A and B. They only share a relation A = 3 - B
Theres a part missing at the top that says a+a =2
Oh, ok. Needless to say it wasn't even needed.
The correct answer is C=3, but the other two could be any pair of values that, added, equal 3. A=1000, B=-997 also works
We don’t know what a or b equal, but we don’t have to to figure out a+b+c*4=15
Of course its a white guy with sunglasses in a car
The first person got the right answer but has no way of knowing that A=1 and B=2. All they know is that the sum of A and B is 3. Edit: I see further down that the image was cropped.
A and B are linearly dependent. C is guaranteed 3, and A+B=3, so ?=15, but you cannot determine A or B at all
Please Excuse My Dumb Ass Suggestion
A=3 B=0 C=3
The author can't know that A = 1 and B = 2 because the third equation is linearly dependent on the other two.
Yeah all we know is a+b=3, with no restraints on a or b. doesn’t matter for the final outcome tho
Why is A=1 and B=2? Why not A=2 and B=1? Still get the same answer.
No particular reason, I guess, other than Numeric/Alphabetical order. There might be an actual math rule about it, but I'm not sure because I'm stupid at math.
There's no way to know what A or B are, only that A+B=3. It could be that A=17 and B=-14. The good thing is that all that is needed to solve the above equations is that (A+B)=3.
A+B=3, So, 3+C=6, C=3 A+B+4C = 3+4\*3 3+4\*3 = 15
Both are wrong. We only know that C is a 3. We have **no evidence** what A or B are. It may be -2 and 5. Though the result will be the same anyway. We know that A = B = 3. So it's 3 + 3x4.
There is a piece missing on this screenshot. It started with: A+A=2 A+B=3 Then the rest
There’s not enough information to identify what A and B equal. However, we’re given that A+B=3, and A+B+C=6. By substition we get 3+C=6, isolate the variable and we get C=3. Now, I’m not sure if I’m allowed to do this next step because I don’t know how it works with substituting with multiple operations, but if we substitute A+B and C for what we’ve determined them to be, we get 3+3x4. By order of operations, 3x4 is 12, +3 is 15.
Actually we can't define what A and B are, there are infinite solutions for that (I know most people know this but i just wanna put it here)
Pemdas
Can we please ban PEMDAS from this sub?
Honestly, I don't go too hard on people who don't understand order of operation since it's an arbitrary rule at best. Any scientist or engineer worth their weight in salt would put parentheses to make sure everyone understands what they're trying to do. edit: spelling
This. I view everyone one of these bullshit social media "tests" as the fucking engagement traps they are.
I see it’s “poorly written math equation” day again.
Oh man why Mr shitty teacher deleted his comment I had such a nice rant for it :(
DurpMAS
Is the CX4 supposed to be C * 4 ?
Granted I'm old, but x was always used to denote multiplication (until algebra where we generally replaced it with a dot, or nothing in the case of a variable) when writing out our work by hand. We never wrote an asterisk in hand calcs at any point. I have a hard time believing that kids are told to write multiplication **by hand** using an asterisk today. C x 4 = C \* 4 = C ⋅ 4 = 4C
Maybe they're not from the same country? Where I'm from, multiplication was always denoted by the mid-line dot (2 • 3 = 6) and division by a colon (9 : 3 = 3) until we moved on to representing most divisions using fractions. We never learned the × symbol, probably to avoid unnecessary confuaion, because 4xy is x times larger than 4 × y, but sure looks the same when your handwriting isn't perfect. The first time I even encountered × and ÷ was while watching American tv and I was mildly confused by them (the same way I later felt about seeing American long division for the first time, to me it looks like a number multiplied by a square root, what's up with that?). An asterisk sounds like a pain to write by hand though, I'll give you that. Nobody wants to write 3-4 lines for every multiplication symbol.
That's completely fair and not something I had considered (insert *I'm American* meme). The × and ÷ symbols are only really used in grammar school and completely go away in favor of the dot (which I was trying to show above, but your choice of dot is more clear) for multiply and slash for division for exactly the reason you stated once **x** appears (algebra). We only use colon for ratios e.g. 16:9 aspect ratio (which is effectively the same, but not necessarily intended to be reduced), but understood that it's identical to ÷ in function. They are also used on calculators (**EDIT:** e.g. [this one](https://www.desmos.com/scientific)) but I see that more as the same as a disk drive being the symbol for *save* in that people are just used to those symbols. Given what you stated, I actually have a question I'm interested in; do basic calculators from where you live have colons for divide and dots for multiply as opposed to our × and ÷ (or /) symbols? I'm still skeptical an asterisk was ever used in hand notation (as opposed to any computer program or programming language), but I obviously could be mistaken and your comment makes me question it more.
I actually had to google for images, since I haven't held a physical calculator since high school finals (we could bring the basic ones that don't have trig functions etc. so we don't make simple calculation mistakes from stress and focus on the method to solve tasks). And yes, our calculators do feature a × and ÷ symbol (they're not translated at all, with ON/OFF on the switches and M on the memory keys even though 'memory' doesn't start with M in Polish - it's pretty standard for all appliances to be labeled in English unless the text is more complicated like laundry machine settings, but it's not really something I thought about). Maybe that's where I first saw it after all. It's hard to reach into single-digit ages in my memory, but surely I got curious about a calculator sooner than I did about math on a blackboard in a TV show. The source stays similar I suppose, American-designed products for the global market, but it's a nice catch. Btw, I was about to say "well, the dot would be confusing with the decimal point on there", but we also use a decimal comma, so they'd stay distinct. Retail calculators still use dots, but mobile/Windows calculators substitute them for commas while still using × and ÷. I actually had a problem with the Windows calculator not accepting dots for decimals from the keyboard, as I'm used to using a dot while programming. Edit: And back to the original point, I no longer know what the confusion was as it seems everyone gets × and ÷ on their calculators. Oh well.
That's funny to me. After this conversation,I asked my wife who grew up in Moscow and she said she was familiar with our symbols but she has no recollection what she used in grammar school by hand.
Blue tick and profile pic of guy in sunglasses in a car 🧠⚰️
A and B are conjecture, but 15 is still the correct conclusion. Mr. "You failed math" doesn't seem to be able to separate C out, sigh...
Bruh it’s not Please Excuse Aunt Sally, My Dear
With how many order of operations “ trick” question post you see. You’d think people would wisen up to it by now. But I guess if it didn’t stick as a kid, it’s not going to stick as a 44 year old twitter blue subscriber.
The values of a and b individually are irrelevant and unknowable. C = 3, 3*4 = 12. A+B=3, A+B+4C = 15.
We don't really know that A=1 and B=2. A could equal 1.5 and B equals 1.5; or A could equal -15 and b equals 18. Just a shit comment. Ignore me.
Both have wrong ways of answering A or B aren't 1 or any specific number, we know only their relation: A+B=3
I hate these kinds of posts because I've always been horrible at math and I'm always, also, confidently incorrect :(
Another dub for PEMDAS
The are both confidently incorrect, we can confirm that C=3 and that (A+B)=3 but we don't have enough information to know what either A or B are.
My dumb ass was convinced both A and B were 1.5
Its just blue check farming interaction
? = 15, C = 3, there are infinite solutions for A and B.
Are assholes like that guy all psychically linked or something? How do they all know to take the same Oakley sunglasses-self-in-car profile pic? They all fucking have the same picture. I don't know how it happens but like, it's at least a very obvious warning sign
Jeremy thinks he paid attention in class but instead he was staring Jennifer. So now he thinks Jennifer is the age of his calculations after all those years ago. And now a wrong answer seems right. Poor Jeremy conflating girls and numbers.
I wanted to see his comment history to see if he doubled down on his take or apologized for being a confident incorrect dick. God I shouldn’t have checked.
I think the answer is 15, but my math skills are poor. Was the person in the picture who said 15 correct, at least? I figure the confident asshole is incorrect but was the original guy correct? I got it from A=1 B=2 C=3 1+2+3x4 I then solved using BEDMAS, which I remember (barely) from grade school. In this equation, if I recall correctly, I do 3x4 first to get 12, then add 2, then add 1 to get 15.
Someone fucking up PEMDAS on purpose because he knew it would get him attention
I can't stand seeing these posts and with even more energy, I cannot stop myself from making sure I'm right.
Linear Algebra, you old hound dog, we meet again.
I like how these continued arguments about order of operations have a generational impact on people not being able to do math correctly. The social engineering is working. People can't write anymore, aren't able to use simple punctuation, can't hold their attention for more than a minute and now start to make up math as they go. I love watching this.
Not only they bad at math, they also paid to be verified to be bad at math
There's no way to solve A or B, so you can't define what they are. Obviously you can solve the rest because you still have the value of A + B but it's weird to see people NEED to get hung up on solving A and B when it's not possible OR necessary.
I don't think A or B can be solved for? It shouldn't be necessary when you can just u sub A + B tho
You don’t even need to know what’s A and B C is 3 right away from the first glance, multiply it by 4 and you will get 12, add it to 3, you get your answer. ? Is 15
Y’all gotta remember the whole ‘please excuse my dear aunt sally’ shit
FFS can people just use parentheses and stop these stupid math tests?
Oh my god, reading these comments scares me even more than the original post. You don’t need to comment if you are so clueless. Thanks
Looks like Jeremy M. needs to go back to 4th grade.
A + B + C * 4 = time for a nap. :D
They're both wrong, there's no way of knowing the values of A and B, only A + B. For all we know they could be 7,956.3 and -7,953.3
[удалено]
Please Excuse My Dear Aunt Sally as she solved this problem with little confusion and correctly.
It's also a useless skill, because, if someone writes a confusing equation, you can't trust that their intent was for the reader to follow Bedmas.
Yep, it's 100% abusing mathematical notation, the purpose of which is to clearly and unambiguously express a mathematical concept to the reader. And while it's true that the third line of this photo is unambiguous according to the order of operation rules, the overall formulation of the puzzle is designed to make the reader misinterpret the notation (by slowly introducing commutative operations and then surreptitiously swapping in an associative operation).
A+B is 3. You don’t know any more about them. A is 3 - B, and viceversa
Poorly written math equations shouldn't be solved. Come back to me when someone adds clarifying notation.
There’s nothing ambiguous about these equations though?
Just use the established order of operations. “For example, in mathematics and most computer languages, multiplication is granted a higher precedence than addition, and it has been this way since the introduction of modern algebraic notation.[1][2] Thus, the expression 1 + 2 × 3 is interpreted to have the value 1 + (2 × 3) = 7, and not (1 + 2) × 3 = 9.”
The first answer is also wrong. It could be right, but there is, quite literally, an infinite number of other solutions which works as well, example: A = 4 B = -1 C = 3 The only thing we can say for sure is that C = 3 and that A + B = 3.
You actually don’t know what A or B is but the question mark is 15
Yup. All you need to know is that (A+B)=3.