Kid gave a reasonable answer without all the math bullshit

This is bizarre. The info provided in the question was that Marty ate more than Luis, the question was how would that be possible given that Marty ate 4/6 of his while Luis ate 5/6 of his. The answer the kid wrote (Marty's pizza was bigger than Luis') is the only possible correct answer.

The grader is asserting that the information given in the question was wrong and that "actually it was Luis who ate more pizza"--even though it stated as a premise that "Marty ate more". How are you supposed to give a correct answer on a test if you are expected to accept one premise (proportion of pizzas eaten) while disregarding another premise (Marty ate more than Luis)? How do you decide which part to disregard? Would they have accepted the answer, "Luis actually only ate 3/6 of his pizza, not 5/6)"? Wouldn't that be just as valid an answer as "Marty actually didn't eat more than Luis"?

Agree, this question is such hot shit that I can't imagine it popping up in any real world maths test
- The question is good, how given one smaller and one larger fraction could the person eating a smaller percent still have eaten more total pizza? That's a fun brain puzzle.
  The problem is the teacher.
- And by gaslighting the kids, they're teaching them not to trust their own ability to reason, crushing their critical thinking skills. It sets them up to submit to authoritarianism and go along with obvious lies instead of trusting their own senses and questioning authority.

that kid passes my class with honors

the teacher is a moron

Same. Question sucks. Teacher is a tool. Kid needs bonus points for a creative solution.
This always pissed me off about all formal school. They don't want a good answer, they don't even want the correct answer. They want you to give them the answer they previously told you to give them, regardless of all other factors.
Real life doesn't work like that. In reality, the "correct" answer is anything that completes the objective. In this scenario, the answer provided was reasonable, logical and most importantly, it was not incorrect.

This is genuinely baffling. What was that teacher on.

The title of this post is disappointing. The given answer is sound and it seems safe to assume it was arrived at by thinking mathematically.

Right? He's rationally explaining how that was possible given the question of "how" it is possible. In my opinion that question was written poorly.

I suspect many commenters are missing the point, the student's response can only be the correct and expected answer to this question. Teacher has it wrong.

No. The teacher did not have it wrong. Does not mean the student is right ... Marty and Luis both had their own pizza. Marty had a big pizza and "only" managed to eat 4/6th of it. Luis had a small pizza, and "only" managed to eat 5/6th of his. If you want to give a nitpicking correct answer: a single pizza does not have (4 + 5)/6th pieces. x/6th implies the pizza(s) were divided into 6 parts ... so: it can only be 2 pizzas.
- Yes, it can only be two pizzas. The question is “how is this possible” which is correctly answered by the student. The teacher talking like that’s not how pizza works, is indeed incorrect.
  4/6 of a 10” pizza is more pizza than 5/6 of a 6” pizza.
- I’ve read this a few times and I’m genuinely not sure I understand what you’re saying.
  4/6th is a smaller ratio than 5/6 the only way for 4/6 to be greater would be for the area to increase.
  Expressed as percentages it would be 66% (approx) eaten vs 83% (approx) where the person that ate 66% ate more pizza. The only way that’s possible is if the area of the pizza that 66% of was consumed was greater. (Strictly speaking the volume could be at play here too but I’m going to assume they’re the same height for the question).
  I genuinely don’t see any way his thinking was wrong, or how this could be answered another way.
  I might genuinely be missing something but if so this question is poorly worded.

Ah, a teacher that does not comprehend the barometer

Two other right answers:

Luis' pizza is at least
<whatever is the correct fraction>
smaller than Marty's (which is basically the same answer as the kid's)
Marty ate someone else's pizza besides his own

And, for funsies:

Luis' pizza is 50% crust, so it doesn't fully count as pizza
Luis doesn't like pizza and actually fed the dog while nobody was looking
Marty is many years older than Luis, therefore he has eaten many years' worth of pizza ahead of Luis

This is completely unrelated but I cannot believe Calandra is a real world name.
The designers of the video game Path of Exile should've called their super rare item "Kalandra's Barometer" instead of "Kalandra's Mirror".
Well the question does assign ownership to the pizza, so Marty can eat his pizza then give it to Luis making it his pizza
correct fraction = 4/5, as in, Luis' pizza is smaller than the 4/5 (80%) of Marty's pizza.

The teacher is fucking stupid. The question says Marty ate more, that is not only possible it is a given.

The teacher is fucking stupid.
The teacher is likely under-trained, overworked, and under-qualified for the class. Common in districts where the focus of the administration is driving down the cost of education rather than delivering the highest quality.
That is, of course, assuming this is a real homework and not some agitprop churned out by a Facebook group or a social media account more interested in generating outrage than education.
- With the choice of marker, I'd say its rage bait.
- "Under-qualified" for the class? Are we really setting the bar beneath the level of a grade schooler?
I agree, the kid is correct. This is the only viable answer.
- Not true. Marty could have also eaten pizza that was not his.

When I was in elementary, my teacher said that "Lutetia" was how the Romans called the city of Liege. As an avid reader of Asterix comics, I knew this isn't true and corrected her and said it was the Roman name of Paris. She insisted that it is Liege. Anyway, the next day, she came back to class and said that she looked it up and that I was indeed correct and Lutetia referred to Paris and gave me a chocolate bar and told me to keep reading comics. Good teacher.

In elementary school our teacher asked us to spell the current year with roman numerals, so I worked out "MCMXCVIII", which I was quite proud of. But the teacher came back at me quite snarkyly and said it's much easier to just substract 2 from 2000, "IIMM" duh!
It was only many years later that I accidently learned that he was indeed full of shit and I was right all along.
- it’s much easier to just substract 2 from 2000, “IIMM” duh!
  For anyone wondering why this is wrong, there are two reasons:
  The roman numeral system only traditionally contains subtractions from the next higher five- and tenfold symbol. So you can subtract I from V and X, X from L and C, C from D and M
  The subtractions only generally allowed one symbol to be subtracted, with a few notable exceptions like XIIX for 18 and XXIIX for 28
- It would've been easier to pretend it was 2000 and just write MM
I had a HS teacher say the the 2nd to 5th richest people were the Walton(of Walmart) family heirs. I knew this wasn't right because at the time, Steve Balmer(of Microsoft) was the 5th or something. I printed out the Forbes list and brought it in. The teacher coped by saying that if you combined the Walton wealth, it would rank that high. He was a POS teacher for more significant reasons than that though.
- I once got in trouble with my math teacher for saying "well if we're just making things up, then sure [I cheated on a math test while sitting in the front of class where the teacher can see but I was using some kind of hidden code on my t-shirt that was a bunch of Shakespearean insults] . But what about all that Crack you were doing in your car this morning?"
  Apparently my "making things up"was a slightly more serious than his. I stand by it. If we're making shit up, we're making shit up.
  For the record, this geometry teacher was convinced I was cheating in class because I didn't do homework. Homework was 5% of the final grade for the year according to his syllabus, I hated homework, so I figured as long as I didn't suck at the rest of the class, I could do 0 homework and pass. I was right, passed with a 94%
In my country, the written final exams include a Q&A section in the beginning of the test, where the teacher and the headmaster are present, and where they present the tasks and students are allowed to ask questions. After that section, the headmaster leaves and students and teachers aren't allowed to talk for the rest of the test.
I noticed a missing specification in one of the tasks. It was a 3D geometry task, and it was missing one angle, thus allowing for infinite correct results. During the Q&A section I asked about that, and my teacher looked sternly past me to the end of the room and said "I am sure the specifications are correct". If there was an actual error in the specifications, the whole test would have been voided and would have to be repeated at a later date, for all the students attending.
As soon as the headmaster was out of the room, he came to me and asked where he made the mistake. He then wrote a fitting spec on the whiteboard.
I liked that guy. He was a good teacher.
I always knew someone else knew about the series!
- Asterix was pretty popular in the 90s Central Europe. The movies were in theaters, the older ones got prime time slots on TV, the comics were in every book store's kids section. I remember laughing my ass off in the movie theater at the scene with the bear when Asterix in America came out.
- An animated miniseries came out this year too
  https://en.wikipedia.org/wiki/Asterix_and_Obelix%253A_The_Big_Fight
- What do you mean someone else? Who doesnt?
haha, I also got some points in school for knowing that Lutetia is Paris, which I also found out by reading Asterix
Dang, in which country are you talking about Liège in elementary school?
- Germany. IIRC the topic was Romans, not Liege specifically.

Teachers that don't accept an unexpected but true answer are not teaching. The test taker had a correct take, one of the pizzas could be bigger than the other. It was not specified in the question. I am so glad I am out of school

This answer shouldn't have been unexpected, seeing as how it's the correct answer.
- The test key has the expected answer, which may even be wrong. If the test taker responds with something else, even if it solves the problem, it is not the expected answer. It's stupid.
It really seemed like my fellow students lost their interest in math as we went through the grades here in the US.
I still remember a kid in 2nd grade who learned how Roman numerals worked because they were interesting. By grade 6, actively detested math.
Curious.
Kid should've gotten half credit at the very least.

i can't fathom this being real, most probably this was made for karma farming or something.

Teachers like this exist. One of my kids had an elementary school teacher like this. Two examples:
The math assignment was about currency denominations; what coins and bills you need to make up $7.42, for example. My kid answered using $2 bills (uncommon in the US but still printed), as we have them at home. Teacher marked the answer wrong because teacher didn't mention $2 bills in class.
The writing assignment was to rewrite the Snow White story from the perspective of another character. My kid, having read a bunch of those "twisted tales" and recently fallen in love with "Wicked", wrote from the evil queen's perspective and made her a sympathetic character. Teacher marked her down for "changing the story" without acknowledging my kid's creativity. Teacher did not back down when we confronted her on this during our parent teacher conference.
(FWIW, in both cases we reassured our kid that they did great in both cases, and that we were proud of them.)
- Teacher : draw a triangle with sides of length 1 inch, 2 inches and 3 inches
  Kid : but you can't do that. You get a 3 inch line. Other students proceed to draw skinny triangles.
  Teacher : you're wrong Kid. Everybody else can do it, what's your problem?
  True story.
Also what teacher uses a green felt tip pen?

Commendable for the kid to be thinking outside of the box, and a bit shitty of the teacher for not giving them maybe half a point (because it's a correct answer, but not the correct/expected answer). The test maker is also to blame - they should've taken care to eliminate all ambiguity - it's a math test after all.

The teachers response is incorrect. It is stated as fact that marty ate more pizza.
- Oh, yes, you're right! I read the question again.
  P.S. And if really is a fake/made up test like some other folks claim in the comments, just look at how much of a discussion it throws us into.
The kid's answer is the only correct answer. It's not half right, or 5/6 or 4/6 right. It's the only correct answer that fits the question. The teacher is a moron who has no business in a math classroom except as a remedial student.
- Marty could've eaten someone else's pizza besides his own, which would also make it a correct answer. The question didn't say he ate 4/6 of his pizza and nothing else
- My wife has pointed out that there is indeed one other correct answer. One kids is bigger -- OR, the other kid's is smaller. TWO right answers.

The statement and question make perfect sense. The kid has the only "reasonable" answer.

Why would you ask "How is this possible" when you expect the answer to be "it's not"?

Teacher got the worksheet from someone else and didn't know the answer.
- Or teacher didn't even see this, handed it to a high school student and said "grade this stack of papers"
  I had that happen several times in science classes in 3rd-8th grade. Eventually I started arguing with the teachers in class, and boy did they not like being corrected.
  Sorry Ms Avery, you not knowing that "Pb" is the abbreviation of the Latin word "plumbum", where we also get "plumbing" from due to its use in piping in rome, doesn't mean I got the answer wrong. To her credit, she looked it up and changed my grade before the end of class.
  Ms hoschouli from 7th grade can get fucked though, a parallel circuit increases amperage load, not voltage load. I knew more about electronics in 7th grade than a college graduate who teaches science class, which in hindsight isn't that impressive considering it was general science and not electronics specific... But in 7th grade, as far as I was concerned I was hot shit for knowing more than the teacher, and getting detention for calling her out in the middle of class. Never got the grade changed and I only got out of detention because my parents called the school.
Because these "teacher is dumber than a child" pictures are always fake. I've never seen a teacher write corrections on a student's paper. Are they doing that for every wrong question on every paper? That would take forever!
- This happens all the time, at least in Germany. My teachers did it, and I do it too.
  The picture is probably still ragebait.
- You can't teach if you don't identify where the students are getting things wrong and correct them. It's one of the major reasons why teachers deserve so much more pay. My wife used to be a teacher, and she worked 2-3 hours past the end of school correcting students' work pretty much every weekday, and spent several hours every weekend planning out her lessons for the following week. She got paid significantly less than me working in a basic entry-level 9-5 office position.
- How are you supposed to learn if they don't tell you how to do it better? Not writing corrections seems like bad teaching to me.
  One of my teachers demanded we fold our paper in half and leave one half empty for his corrections, another one demanded a third of the page, and the rest squeezed their comments on the edge of the page
- Some people become teachers because they love to educate children.
  Some people become teachers because they have no control in their life and want to be the boss if something.
- Are they doing that for every wrong question on every paper? That would take forever!
  I work in education in Texas. Yes, they do. And yes, it does. Now, most things are digital, so they have kids make a copy of the Google Doc and then grade that and leave comments on it. But if they have paper assignments, they often leave notes on them. Leaving notes on assignments and tests/quizzes (which is likely what this was) is part of their professional review.
  Also, part of their regular professional review is whether or not they're keeping proper documentation on student behavior. Different tiers of behavioral issues require different documentation/communication. So, not only are they writing notes on tests/assignments, they're writing documentation on hundreds of students, contacting dozens of parents, creating lesson plans that have to be available in advance for parental review in case any parents want to dispute the materials, and they're getting regular reviews.
  And then, when all the kids are off enjoying summer, the teachers are working their summer job to supplement their shitty pay. And they're going to mandatory "Professional Learning" courses to keep their teaching certification, some of which they are required to pay from their own pocket to attend.
  In San Antonio, we don't really have any "small" districts, so the numbers in the second paragraph assumes an elementary school of 300-600, middle school of 800-1200, or high school of 1200-2000 students.
- I was told in 6th or 7th grade science class that you can't hear underwater
- Ohio resident for grade school, they did it at 4 different school districts across every grade.
  Can't speak for anyone else.
- Because the teacher is wrong and it’s an idiotic question.
  The question asks the child to explain how Marty ate more pizza than Luis. “He didn’t” is not an appropriate answer to that question.
  We know that Marty and Louis didn’t eat from the same pizza, because Marty ate 4/6 of a pizza and Luis ate 5/6 of a pizza. We also know that Marty did eat more, because it’s right there in the question.
  The only logical answer is that Marty’s pizza is bigger, and so 4/6 of his pizza amounts to more pizza than 5/6 of Luis’s smaller pizza.
  The question should have been “Marty ate 4/6 of a pizza and Luis ate 5/6 of a pizza. Explain who ate more pizza.”
Because they spent an entire math class period earlier that week explaining to the students what "reasonableness" was going to mean on their next math test, and in the context of (I'm guessing 3rd or 4th grade) arithmetic the important thing they're trying to teach is that 5/6 is a larger fraction than 4/6. I agree that the question could be worded better (change the last two sentences to "Marty says he ate more pizza. Is this possible?") but I strongly suspect that the missing context from their class - or maybe even at the beginning of the test - explains enough to get the answer the teacher was looking for here.
Yes, one kid starting with a larger pizza changes the situation, but fundamentally that's an algebra question, not a "learning fractions" question.
- Well yes it is a learning fractions question. Pizza is not a number. Pizza is not a specification of size. It is absolutely crucial for understanding fractions, that a fraction of anything but two numbers will be factored by the size or whatever metric of that thing.
  In the same wake you learn that "5" is not an answer to a typical physics calculation, as the unit is missing.
- We can understand the context of the curriculum goals and still realize that the question was asinine and the teacher is a dipshit.
- You could argue that it's reasonable to assume that all pizzas are the same size but there are many pizza places that offer different sizes. You could as well argue that this is an attempt to make the kids think outside the box and come up with this explanation. How big a fraction is depends on how much the whole is is a good message you can't learn too early. Understanding statistics is in large parts this. Many people will throw around percentages of pooling questions without ever questioning the pool of people asked.
- I agree that the idea they were teaching was "is it reasonable for 4/6 to be larger than 5/6", but it was too sloppy to be in a word problem with cultural context. Sometimes if you're the teacher and a kid stumbles onto a loophole this big, you have to take the L and update your materials for the next year. Just add, "Marty and Luis ordered small pizzas at Joe's," and this goes away. This feels like the question writer had been in a groove with drafting more abstract problem sets, and didn't do a good job when shifting gears into the word problem section.

Curriculum and unappetizing methods of teaching are the problems.

This kid has the right to question, to speak out what's really logical, and is likely to be more street-wise.

The equivalent of whats going on in the teacher’s head.

Actually a kilogramme of feathers is heavier, because you have the weight on your conscience of what you had to do to those poor birds to get all those feathers.

I... Um... I've been looking at this for a minute and I can't tell why the answer is unconventional, nor what the fuck the teacher is on about.

The kid answered correctly, it's not unconventional at all, the teacher is just stupid
It’s fucking dumb. No where did it say the pizzas are equal size. So the kids answer is just as right as her bullshit answer.
- No, the kid's answer is not "just as right", it is the correct and expected answer. The teacher's answer is wrong and proof the teacher doesn't understand the question. The entire point of the question is understanding that fractions of a whole are relative to that whole and you can't directly compare fractions from different wholes like that. 5/6 > 4/6 doesn't mean Luis ate more pizza than Marty, it means Luis ate a larger share of his pizza than Marty ate out of his own.
- But... The teacher is just flat-out wrong. It says right there in the problem that Marty ate more, and then uses that fact as a foundation for the question of "x is true, HOW can x be true". It'd be different if the question was "someone claims x is true; is it?"
- The kid actually answered the question. The teacher's expected response is basically "no, your question is wrong and I refuse to answer it."
The question asks "How is this possible?"
What they mean to ask is "is this statement true if both pizzas are the same size?". To test whether the kids can compare fractures. It's wrongly worded and the reaction is bad. If any of it is real.
I'm actually not sure this is real. I've had some shitty abusive teachers but even they would be capable of basic logic.

If you state that Marty ate more as part of the question, you cannot answer in any other way, because it denies mathematical logic here. You introduced a lie as part of the problem, and if I need to decide myself which part of the statement is a lie, I can pick whatever I want, let's say, Marty didn't ate 4/6, but 6/6. This teacher should be taken to the gulag.

Yeah, this is answered exactly correctly, and also demonstrates that the child has a strong grasp of how fractions work. 3/4 of 2 is greater than 4/4 of 1, even though 4/4 is a larger fraction than 3/4.
- Yeah, that was my point. If everything the question says is true, the only way 4/6 is more amount pizza than 5/6, is that the first one is a bigger pizza. The kid not only understood the logic with fractions and the problem statement, but came up with a really good answer. You can even calculate how much bigger the pizza is.
  Teachers accepting only "the right answer" without pondering that kind of thinking, are really just damaging kids. Straight to the gulag.
Pretty sure its a joke and not a real exam.
- "Reasonableness" as the heading implies that they've been working on whether a word problem makes any sense at all. It's, perhaps ironically, an attempt to help them build critical thinking skills. Then, elementary school teachers are not all brilliant minds themselves, and even the ones who are incredibly gifted educators are overworked, and their schools are generally underfunded. You get a cheap resource, maybe even a free one, or one your former mentor threw together late one night three years ago, and you can end up with a sloppy question. If you yourself are having a bad moment, or are not particularly talented, or the kid is a known shitass, then yeah, you could overreact and respond like this.
  Having just sat with my kid through a year of 5th grade math homework, it is completely plausible that this is a real quiz and a real response. Some of the question writing even in the professionally made materials is just not good, partly because it presumes a laser focus on a single "instructional variable," despite mandates to teach holistically.
You introduced a lie as part of the problem
There is no lie or contradiction in the problem, what are you smoking? The kid's answer is exactly correct.
- They're not on about the kids answer. They're talking about the teacher saying Luis ate more. How? It literally says in the question Marty ate more.
- Marty ate more than Luis, that was she lie, in the problem not the answer. That's if the teacher is saying the answer isn't right.
You miss the understanding that the kids would have been coached everyday for at least a week to look for the fractions and compare them. And not be overly concerned with anything else. The kids aren't stupid, they know that they have spent the week comparing fractions and that's what the test/quiz would cover. I would bet very long money that the majority of the students got the correct answer and those that didn't, simply chose the wrong answer. Still, you do get an oddball answer on occasion. Because young kids are cool like that sometimes. It's a minor thing to correct as a teacher.
As an adult, you are reading far too much into the question because you want to be angry.
- That's not what it is, no.
  Teachers make mistakes, like any human being, and a good teacher can deal with the fact that they made a mistake and that a student found said mistake.
  A teacher who insists on being right over being correct is a bad teacher, because a teacher is supposed to teach a child understanding and knowledge, not blind obedience above anything else.
  That's how you end up with a population who agree with the leader even if he tells them the sky is green.

Given 4/6 x > 5/6 y therefore x > 5/4 y

Marty's Pizza must have been more than a quarter larger than Luis'. The kid is exactly right.

And the teacher is not flexible enough to engage outside their expectations for how the question was supposed to be answered.

Clearly the expectation was for the kids to take the unstated assumption that the two pizzas were of the same size, and reject the premise as unreasonable (note the heading "Reasonableness").

I'm pretty sure the kid's answer was how it was supposed to be answered
- Honestly I suspect the question was phrased poorly. It should have simply said "who ate more pizza" not stated who ate more and request to explain how
Now we know why teacher isn't teaching math, but they should definitely not be teaching reasonableness either.

Take that to the principal, stupid teachers shouldn't teach

Reminds me of the time when I got send to the principle for saying "fuck you" during class. I was saying it to a classmate, but the teacher felt it was directed at her.
Anyway, the principle (herself a German teacher, this happend in Germany) gave me detention and wrote a letter to my parents, saying it was because I made a sexist remark towards a teacher.
My Dad wrote back explaining the difference between a sexist and an obscene remark. They canceled my detention.
- I was once called down to the principal’s office and told I would be expelled from my Catholic school because in spite of my catholic upbringing, I was an atheist (in the US, at a time when this was obviously illegal, given that the school accepted non catholic students of other religions). They called my dad and had me wait in the hall outside the principal’s office. For context, my dad’s an agnostic who doesn’t harbor any positive views towards the Catholic Church, but is a huge fan of educators and would always side with the teacher, no matter how unfair they were being.
  My dad went straight in without acknowledging me and spoke with them inaudibly for about a minute, before the secretary came out and sent me back to class. I never heard anything about it from the school again and when my dad got home, he just said I didn’t need to worry about it. Decades later, he still won’t tell me exactly what happened, but I honestly think he might have forgotten and doesn’t want to admit it.
- Das ist echt krass xD Dein Papa hat vollkommen Recht
The principal is not necessarily any smarter than the teachers. Often it's the opposite.
... or have a bit of empathy and talk to the teacher like a human.

I can't find it now and I do not think it really applies here. But someone stated that being high IQ could lead to academic problems as the high IQ learner would understand or see things that the professor could not causing the professor to mark it as incorrect.

I guess this is the idiocracy version of it.

A good teacher sees being corrected as a learning experience, and encourages their students to question them respectfully.
Bad teachers see it as a challenge to their authority.
I think this would more likely be an overworked and underpaid situation.
- If I were an overworked teacher, I'd still rather award the point. Just throw down a checkmark and move on. I don't need to write an explanation, and the kid/parents are not going to complain.

It is entirely possible and his answer was correct. Question was phrased incorrectly, if the teacher wanted an answer "it is not possible" he should have said both pizzas were the same size.

Not only that, the two statements in the premise are simply given. How is the child to know one of them is false? At that point, why not say Marty ate more than Luis and therefore the fractions must be different? Maybe the fractions are wrong and Luis ate more.
Just an absolutely terrible question if that's supposed to be the answer. I'd guess the teacher didn't write the question and didn't understand the answer.
A third option is that there is a third pizza eater who also ate 4/6th of their pizza and gave 2/6th up Marty in exchange for the 2/6th Marty didn't eat.
Or yeah maybe it was a larger pizza.

So this was a trick question? Because the student's answer is correct. That's the only way it's possible. Was the answer supposed to be that it's not possible? I'm a grown adult and I find this question unclear so I'm surprised this was asked to a young child in this way.

Well the teacher's answer is flat out wrong which doesn't surprise me at all.

The teacher is the one who's confused here. The kid is entirely correct.

"This is not possible because..."

This kid is never going to trust teachers again.

He was right. The question is not even worded ambiguously. It was just written very poorly.

Will the teacher admit that? Or is the expectation that this (likely neuro divergent) student should have just understood the expectations based on context clues or something?

Valuable lesson learned, trust yourself instead of authority ( I hope at least that was it and not start of self doubting ever after)
This kid is never going to trust teachers again.
If one bad response is enough to turn you off from anyone else teaching you anything ever, then you're carrying some enormous trauma that has nothing to do with a single math question.
If one bad response is enough to open your eyes to the fallibility of individuals and lead you to think more deeply about where you get your information and how you evaluate the correctness of a response, then you're going to go far and develop a much deeper understanding of the world.
- But those things stick. I did a geography test 35 years ago and wrote Canada instead of Kanada wich which is the correct spelling in German. In the eyes of my teacher I answered the question wrong and didn't get the point, but I also got a point deducted because I did a spelling error. I didn't lose trust in teachers or society in general, but this still nags me. :)
- You are massively not comprehending how a child thinks.
The question is not even worded ambiguously. It was just written very poorly.
Its not a Maths test. Its a comprehension test.
- Which the teacher failed (assuming this is real)
This kid is never going to trust that teacher again.

This brings back memories of when I realized that I was smarter than most of my teachers.

Marty's pizza is larger. 4/6ths of a 3kg pizza is more than 5/6ths of a 1kg pizza

Some real "steel is heavier than feathers" energy coming off this teacher.

The statement and the question do not make any kind of sense. Would make more sense to ask who ate more pizza when one ate 2/3 and another one ate 3/4 of an equally sized pizza.

⅔x > ¾y when x > 1⅛y. The question helps you parse word problems.

Math education in the empire is TERRIBLE. There is no actual math taught. At best it's applied analogies like this pizza BS. The teachers have never taken any advanced math so they don't even know what they're not teaching. The goals (eg. calculus) are completely worthless. The entire system is stuck in the 1700s. It's a complete failure. It's intentional too. The goal is creating obedient, little computers not critical thinkers. That would be a threat to the system. This image is just the tiniest tip of the iceberg.

George Carlin on education.
- We're in the cursed timeline where Carlin didn't lead the second American revolution.
  Real talk though, it's because we don't have an education system, we've got a babysitting system. POSIWID.
The empire?
You might afford too much malice to something that might be just a generational incompetence and total lack of care. Smart kids don't increase this quarter's profits, therefore are irrelevant.
- Thats an awfuly convenient incompetence for the ruling class then.
  Also, I dont know how things are where you live, but here in méxico we keep hearing, year after year, how topics and subjects are removed from school plans. Seems like a very obvious effort to "teach less" every year.
- No. See sibling comment where I linked to George Carlin.

lol this is actually a golden answer and that is why we need better teachers

In my experience this is how it feels to communicate as an autistic person

Interesting, I'm autistic and what frustrates me here is that the question specifically asks you to posit "How is it possible" and the teacher insists that you're supposed to just say that it's not. Makes me want to just Calvinball the whole damn exam. 5 + 7, what is the answer? Purple. Obviously.
- And it’s not even some crazy stretch to make the premises work. Like if it had said the pizzas are the same size, I’d have to try to come up with something ridiculous to meet the requirements of the question, and would probably just leave it blank. But people order different sized pizzas every day.
  The “correct” answer contradicts the requirements set out in the question.
  Am I autistic? Or do I just have basic reading comprehension?
  If the “correct” answer is valid, so is “actually neither of these people exist”, because we clearly aren’t expected (or allowed!) to accept the premises for sake of argument.
- I’m not autistic but agree that the kid gave the correct answer and the teacher is wrong.
  If that had happened to my kid the teacher and I would have had at least one meeting.
Most threads on here remind me of that

So...

        (4/6)m > (5/6)l
    m > (5/4)l

Which means Marty's pizza is more than one and a quarter the size of Luis' pizza. We can comfortably just compare the area, since we can assume a flat disk with equal height for a pizza.

Assuming Luis' pizza is a Domino's Classic size of 25cm that's an area of:

        (25cm / 2)² * π = (625cm² / 4) * π = 490.874cm²

So Marty's pizza should be more than 490.874cm² * 1.25 = 613.5925cm² for 4/6 of his to be greater than of 5/6 of Luis', so:

        sqrt(613.5925cm² / π) * 2 = 13.975426964cm * 2 = 27.950853929cm

Since Marty's pizza is greater, let's go with 28cm diameter... which happens to match exactly a Domino's Medium size.

That's a very realistic scenario and the teacher is an absolute idiot for not understanding.

This post shows the difference between school and education. The school system is there to get a child to be able to regurgitate whatever the lesson says they should. Education is to develop knowledge as a whole.

It is sad that the teacher was not even able to consider the flawed nature of the question, because they are trained to just see if the student's answer matches the answer key for the test.

In many cases, the public education system no longer exists to deliver educated graduates. It exists to feed itself -- to obtain funding for itself the next year and to support a gradually expanding set of "administrators" that add little to the process.

Look at the effects of "No Child Left Behind". NCLB pushed test scores above all else. What did we get? A bunch of students that were very good at passing standardized tests. That does not necessarily translate to a better educational outcome. The value in the skill of passing standardized tests plummets rapidly once one joins the workforce.

There's nothing wrong with the answer.

If I ate 1/4 of my pizza and my gf ate 1/1 of her pizza, but the hidden context is mine is from Costco and hers is from mod, who ate more pizza

Was the costco size a cheese pizza, or pepperoni?
- I worked there before a few years ago so I may be a little inaccurate, but somewhere in the realm of 18"-22".
  They are massive, definitely bigger than your usual pizza delivery box/bag

I have an argument like that in my calculus 1 class in college, it was an optimization problem but the professor never said that the optimization variable was a constant, so you couldn't differentiate it to zero and do the normal process that you typically do. So I just wrote that given that the perimeter wasn't a constant the area to optimize goes to infinite Givin x -> inf; y -> 0, without loss of generality. He marked me zero we discussed about it and I said that I don't care because I'm going to get a 10 next test if he didn't fucked up the question. At the next exam I made some stupid error but he still gave 9/10 for the overall class because he came to accept that he wrote the question wrong and I was the only in the class actually caring and giving the class some dedication.

Your fault for not listing the size and list of toppings for both pizzas, one could be a small personal pizza size with just cheese and pepperoni and the other a full huge New Yorker sized one with double of everything.

Shit, pne was probably a pizza bagel and the other a Pizza Hut Bigfoot.
Just to prove the point in an absurd way.
- Or even a step further, the measurement is in volume not area. This could be a Chicago style pizza where 1 slice equals 2 slices of New York style.

it's fairly clear there are two pizzas, but as to 'how' someone eats more than someone else... this is not really a simple math question, there are too many unknown variables. Maybe one has Bulemia, maybe one of them is 6'9" and has a much bigger appetite. Maybe one of the people has a congenital deformity resulting in two mouths... This question is not a math question, it's an exercise in creativity.

Even if it is purely a math question though, it never specifies "Their pizzas are the same size." The student literally answered how this is possible in a reasonable way that satisfies the mathematical requirements, when the teacher is expecting an impossible answer of "it's not" after saying in this scenario that Marty did in fact eat more.
- Yeah, if the question was "Is this possible?" then the teacher's answer would be reasonable.
  But the "how" in the question implicates that it's actually factual and the student should come of with an explanation how. Which they did perfectly.
How did they eat it?
They put it in their mouth, probably chewed a few times, swallowed, and then repeated the process as needed.
Q.E.D.
Yeah but none of those are relevant to this question?
- My point is the question is terrible, and one might as well answer however they like. It's a basic logic test dressed up in fractions, the only answer is one pizza is bigger, but that's apparently wrong, so you HAVE to be creative in describing how to solve the logical problem. Does this help you?

How ruined the question

I know this is bait but who said they had the same-sized pizzas?

One could be XL the other one a personal pizza.

I know this is bait but who said they had the same-sized pizzas?
That's a base assumption when you compare fractions in these word problems.
- Assumptions make an ass out of you but not me

Is there any reason at face value why the teacher’s answer is correct? From my perspective the teacher is an idiot and missing some basic math skills.

Marty ate 66% vs the other kid’s 83%, no way “marty ate more” with the information given.

The question literally says "Marty ate more pizza". It's a foundational fact that you're given as a part of the problem. If refuting the basic facts of the question are on the table and the answer was the say "Actually, no he didn't" then you might as well say something like "No, he actually at 1/6 of his pizza" and claim all the numbers given are dishonest.
no way “marty ate more” with the information given.
that is the 'Expected' answer
- So this is sort of a true/false math problem given to us, the viewer, out of context.
No. Within the parameters of the question it IS possible and the kid gave the correct answer.
A small fraction of X can have a greater absolute value than a large fraction of Y when X is suffienctly larger then Y.
reasonableness
This is likely a question about some topic on reasonable questions and answers, rather than a maths question.
- If I saw two people order different sizes of pizzas, my mind wouldn’t be blown, and nobody would consider the situation unreasonable.

Ahh, fractions and word problems, the bane of my education (seriously, why do we bother with fractions when decimals are easier to compute and express?)

Imo fractions are way more simple in many cases than decimal numbers. Saying 1/3rd is way more useful than hitting someone with the 0.33333333333333.... Quick mental computations with fractions are also simpler in this case. Though this question (and questions like it) seem useless to me indeed.
- I mean I understand, but in the case of .33333333333333... isnt it actually represented as "point three repeating"?
- Or just say 33%?
who says, 5/6 is easy to mentally understand than 0.83־.
is a reasonable way to start thinking about arithmetics, and basically to start doing simple math IMO.
Man, if you can't understand fractions, you don't actually understand the math, you're just trained to use a formula.
- I understand fractions, I simply doubt their utility.
The higher the level of the course I was taking, the less test markers cared about the actual final answer. If you used the correct equations, simplifying the final answer to a faction rather than a decimal or leaving constants like pi and e in there was good enough for full marks.
Generally more accurate, too, because you're not rounding the number but leaving it as the true value because 1/3 != 0.333333. It's better to do it this way if there's multiple steps, too, since you can gather or cancel out like terms if you leave them as variables instead of converting and rounding to some decimal.
People have already commented on fractions, there's a lot of math that is way easier to keep accurate by leaving in fractional form as it goes.
For word problems, done correctly, the math is pointless if you can't map it to more realistic scenarios. In terms of applying math to the real world, it's supremely rare that the world just spits out the equation ready for you to solve, the ability to distill a scenario described by prose to a mathemetical solution is critical. Problem is when they are handled incorrectly and have ambiguous solutions or parameters, but dealing with kids' homework, this is pretty rare, though it's admittedly utterly infuriating when it comes up.

I had situations like this at least a few times a year in school.
I usually managed to convince the teacher I was right.

And yah this kid is almost certainly ND.
Not just the answer, but the handwriting screams dysgraphia.
It looks a lot like mine.

Or the kid just understands the given scenario and prioritized coming up with a valid answer instead of assuming the question is bad. You don't have to be ND to be thoughtful/observant or to be surprised that the question expected to be called out as wrong that early.
On the handwriting, it could be that, or it could be typical elementary school handwriting. Or someone imitating elementary school writing for internet points in a fake math question.

The writing looks like first or second grade. Where do they teach fractions in that grade?

That looks like my writing now, and I’m in my 30s.
- Damn, hope you graduate to Third Grade by 40!
- As a very old lefty, I wish my handwriting looked that good.
Boys in particular, (though girls are not exempt from poor handwriting), will have "poor" penmanship pretty much all through elementary school and even into Jr High. And fractions are generally introduced at the end of the 3rd grade school year. And based on the question, that's the likely grade level that test was created for.
I would bet that most of the students in that class got the answer correct because they were coached to read the question correctly-- to look for the fractions and simply compare them. And anyone else that didn't, simply chose the wrong answer. Still, you will get a surprise answer like that every once in a while because kids are cool like that. It's worth a chuckle as you move on.

Cancel that teachers staff pizza party in lieu of a payrise pass.

Reminds me of the stack of frozen mini pizzas you could get in the 80s.

Neither is right: written text is not people, and text without people is either right or wrong until someone read. Only people reading can make the text true, also, you're a moron.

...it's just a joke, jeeeez.

Marty ate some of someone else's pizza

You know we wouldn't even really need fractions if it wasn't for your stupid inches and feet right?

Metric countries have no real use for them

I sincerely hope that was a joke...
- don't worry. they're only 1/2 as intelligent as 50% of average morons.

This is literally a trick question.

No it's not, it's rage bait.

reasonableness

Every time this gets reposted, everyone misses this first word.

This isn't a maths question.

It's asking the student to read the question and make an observation if it's a reasonable question and answer.

And with the information provided it's not.

But it's perfectly reasonable for Marty to order the bigger pizza because he is a greedy bastard.
I'm sorry, what? There is precisely nothing unreasonable about this question. It has a correct answer that can be found with basic logic
- Yeah, most pizzerias sell many sizes. Both answers are valid.
  In fact, i would argue making an assumption, in this case about size, without declaring it, is in fact less reasonable.

The question is stupid, but the kid's answer is still wrong.

How is it wrong?
- It's a basic assumption in these word problems. For instance, when they ask you to compare 2/4 and 2/8, you know that you can transform 2/4 to 4/8 and see that it's greater than 2/8 (0.5 > 0.25). It's a basic school program, there are no tricks here. It's a pure math exercise.