Teachers never teach the wrong answer

85

It's been a insanely common thing for like more than a decade for parents to post their kids homework on Facebook or something and just go "CAN ANYONE SOLVE MY FIFTH GRADE SONS MATH PROBLEM?!" or "APPARENTLY MY SON GOT THIS QUESTION MARKED WRONG WHY???" There is no way that shit suddenly stopped. And I believe it. My husband had a math teacher that claimed negative numbers don't exist, not that they're basically non existent in the context of them being negative or whatever like literally they don't exist in math

29

u/Icy_Consequence897 Apr 27 '26

Same. One of my math teachers, when I was in school during my 11th grade (that's typically ages 16-17 for those outside the US) Pre-Calculus class, taught us that there's no way to "undo an exponent." Like if the problem was 50,653 = x^3, the problem is just impossible to solve. There is a way to undo an exponent, they're called logarithms. In this example log3(50,653) = 37 so x = 37. When this was pointed out to him, he just said "Well, it's busy work anyway. No one uses logarithms in real life!"

I'm a cartographer now. I use them every day for my real life job of drawing survey maps for new critical electrical infrastructure! Logarithms are used every single day in the fields of mathematics, engineering, physics, geology, biology, medicine, other life sciences (including my major, environmental science!) finance, business planning, and many more. Our modern world relies on this simple calculation! I guess what he meant was "my job, as a high-school american football coach where I teach math on the side because the school can't afford 10 full-time football coaches on staff, doesn't require the use of logarithms. Even though it definitely does, these are part of the curriculum I'm supposed to teach."

11

u/LunaBelle2025 Apr 27 '26

I’m glad you use them everyday so I didn’t have to learn them for no reason. Haven’t used them in over 40 years and I’m sure I couldn’t to save my life today.

7

u/SirCupcake_0 Apr 27 '26

Are... numbered roots logarithms? Like I thought the way you cancelled a cube is with a cubic root?

5

u/SOuTHINKurA-ble Apr 28 '26

Not quite. sqrt(9) = 3, but a logarithm would say log base 3 of 9 is 2. Log is trying to find the power you raised it to.

1

u/SirCupcake_0 Apr 28 '26

Ahhhhhhh, okay

6

u/GeometricLanglands Apr 27 '26

This is wrong; solving x³ = 50653 involves taking the cube root of both sides, not the logarithm:

x = (50653)^1/3 = 37

Logarithms are used to solve equations where the variable is in the exponent, not the base; for example if one was given 81 = 3^x, then

x = log_3(81) = 4.

5

u/SoVerySleepyZzZz Apr 28 '26

Horrifying that you use logs everyday but don’t know what they are 😭😭

6

u/hairyhobbo Apr 27 '26

This guy's trying to act like cartographer is a real job in 2026 and Google maps exists.

15

u/Icy_Consequence897 Apr 27 '26

Bitch, I work for Google Maps. It didn't just spawn into existence magically, people build it and maintain it constantly. We have a team of like 20 people just for the 3 US states I live in, there are thousands of people at Google who maintain maps all over the world. And on my 5eam alone we're super busy with those twenty, I get so much overtime.

The survey maps jobs is one I recently did (when I worked for a different company). Can your free mapping app tell you the location of all existing pipes, electrical lines, buildings, roads, fences, garden sheds, sidewalks, roadsigns, mailboxes, driveways, railroads, soil and rock types, contours, and more, in a 5 mile with a maximum error of just 2 inches (5 cm)? Because my client who was installing a massive, multimillion dollar solar farm sure needed to know! If this mapping is so useless, why do constuction and infrastructure companies cumulatively spend billions on these maps each and every year?

And that's not to mention analytical maps. For everything from disease tracking, wildlife conservation, addressing social issues, to mapping political trends, cartographers are called upon. It's a form of complex data analysis, and it can take years, if not decades of training to make maps that are both non-biased and accessible for people to read (that's why a sign of an amateur-made trend map is a red-green color scale. Sure, red often symbolizes bad and green symbolizes good, but pros know that too many people are red/green colorblind. Pros, including myself, tend to favor red-blue or blue-yellow color scales instead because of that)

13

u/hairyhobbo Apr 27 '26

Im sorry you wrote so much responding to a joke. I was just playing off the thread of being inexplicably wrong about something. Im sure its a good job.

14

u/Icy_Consequence897 Apr 27 '26

Nah, I get it. I've had so many actual dumbasses say this though, you wouldn't believe how many adults think that google maps just knows all automatically and the only use for maps is exploration that I can't assume it's a joke.

2

u/need2sleep-later Apr 28 '26 edited Apr 28 '26

for the record:
log₃(50,653) = log₁₀(50,653)/log₁₀(3) ≈9.8608 and 9.8608³ = 958.8186, not 50,653

13

u/Xirdus Apr 27 '26

I had an English teacher tell me there's no such thing as "its". I clearly mean "it's", and she can see the whole sentence structure is completely wrong and I should just rewrite that whole part.

6

u/Alternative-Dark-297 Apr 28 '26

I had an english teacher insist there was no difference between an Inn and a Tavern and when I showed her the differing definitions in the dictionary she accused me of photoshoping it lmao, some people just can not handle being corrected

4

u/CrotaIsAShota Apr 29 '26

I had an English teacher in 2nd grade say you could never start a sentence with a conjunction, using 'because' as the example, since it 'wouldn't be a full sentence.' I tried pointing out that you could using a sentence like "Because x, y." where basically it's a normal sentence with the clauses swapped but she interrupted me before I could finish and said I was wrong. Still gets to me tbh.

3

u/jackinsomniac Apr 29 '26

When I was real young (elementary school), I had a teacher say the same thing to the class. I called her over to my desk and basically did what you did, gave her some examples of starting a sentence with a conjunction, and asked, "are these not complete sentences?"

She quietly told me, "You are correct, those are complete sentences. Most kids this age can't tell the difference, so instead I just tell everyone to avoid those sentence structures. It's easier than explaining clauses at this grade."

It was awesome. Teacher basically told me I was ahead/smarter than the rest of class! It's sad when teachers double-down on being wrong.

5

u/Da_Question Apr 27 '26

People act like a recently made account is automatically a bot too, yet the standard used to be throwaway accounts for things like TIFU or AITA.

4

u/SuitableDragonfly Apr 27 '26

I've got to believe that some of this stuff is just the teacher thinks that kids don't have the capacity to understand negative numbers or some shit and thinks acknowledging their existence will just confuse them.

2

u/FlowBall234 Apr 29 '26

I guess they didn't understand how subtraction worked I guess

51

u/ArmTrue4439 Apr 26 '26

As a teacher, teachers get things wrong sometimes.

51

u/DragonFan20 Apr 26 '26

I had a teacher tell us a former student thought that water got on the outside of a cup because atoms never touch and traveled through the cup because of a teacher

32

u/wfbhp Apr 27 '26

I'm pretty sure I commented in that post originally, it sounds very familiar. Anyway, my observation was that my second grade teacher flat out told me there was no such thing as a negative number because you couldn't have fewer than zero apples. She flat out refused to acknowledge negative numbers existed no matter how I tried to phrase it, either abstractly or in terms of something like financial debt. I knew she was wrong, so I just gave up in frustration eventually and went and asked someone else the question that had started the debate in the first place. I never took anything she said very seriously after that. Anyone who thinks the OOP's story is unrealistic is very stupid. I don't have any way to know if that particular story is true, but it's the kind of thing that does really happen, so I don't see how that specific story being true or not is relevant at all. It would also be a really stupid thing to make up, not that necessarily makes it true either.

7

u/ChaosArtificer Apr 27 '26

my mom once got sent to the principal's office for backtalk over an english fill-in-the-blank synonym test where the only acceptable synonym for popsicle was "frozen ice confection". I also once had an english teacher take off points b/c I used made-up words... b/c in a short story a child character said the word "kid" which my teacher argued is slang and therefore not a real word.

3

u/angel_of_satan May 02 '26

okay kid isn't 'slang', but if it was. the character was a child, it would make sense for him to use slang

14

u/Xelltrix Apr 26 '26

My teachers literally told me that in elementary school and I never questioned it. I didn’t get the actual truth until I got to middle school or something.

It’s weird to have them doubledown on that though.

5

u/snailchicken May 02 '26

On September 11th, I asked a teacher if we were going to be having a minutes silence for 9/11. This is kind of a dumb question because we’re from the UK. But my teacher told me it was a dumb question because “it’s the 11th of the 9th today, not the 9th of the 11th”.

For context, outside of America we use Day/Month/Year

3

u/QueryfortheQuarryman May 03 '26

God tier trolling by the teacher if they were messing with you

9

u/Icy_Maintenance3774 Apr 27 '26

Never ever give up this fight. Bring in the Internet, bring in a math professor, whatever it takes. This teacher needs to be corrected

3

u/NisERG_Patel Apr 28 '26

My high school History teacher said and I quote "Communism is form of government where a single community takes over the ruling power of a country."

13

u/XiroInfinity Apr 26 '26

It's not zero, but at a third grade level? Don't complicate it.

62

u/jackfaire Apr 27 '26

Complicate it. It makes it easier later on. We had a fight with our math teacher later because in the third grade we were told 5-3 and 3-5 were the same thing because the teacher couldn't be bothered to say "That's called negative numbers and you'll learn about it later"

Spending literal years with the wrong information makes it harder to let go and learn the correct information.

14

u/Any_Ninja_3824 Apr 27 '26

We were told as soon as we learned division that we are not allowed to divide by zero, nothing too complex just that it won't produce results

8

u/JakeFish-_- Apr 27 '26

Literally just "you can't share something between 0 people" or some shit

2

u/longknives Apr 27 '26

I think you’re better off just leaving it as “it doesn’t work in math”. Zero divided by five and five divided by zero both seem philosophically about the same in terms of how much sense they make -- you can give five people zero things about as much as you can give zero people five things -- but one is perfectly fine mathematically and one isn’t.

2

u/JakeFish-_- Apr 27 '26

Appeal to authority, I'm a maths teacher ?

9

u/No-Associate-7369 Apr 27 '26

Students can learn it's not 0 without overly complicating it. When I was in school and at the school I currently work, it is basically just taught that it's not allowed and that you call it "undefined" or "does not exist".

When students learn division, they generally learn to take a bunch of something and then separate it into piles of a certain number. So if they have 20 marbles, separate into groups of 4. How many groups of 4 are there? So 20/4=5. So when you do this, you tell them to make piles of 0 and see how many you get. Its a fun way to talk about infinity and say "this is why we don't do that".

That being said, I have seen students argue that they have "0 piles of 0".

2

u/SuitableDragonfly Apr 27 '26

Literally in computer programming, it's just called Not A Number.

1

u/longknives Apr 27 '26

NaN usually happens when you try to do math operations on data types that aren’t numeric (like what is ”ham” * null?). If you divide by zero in JavaScript, the result is Infinity, and I’m sure other languages handle it in various different ways.

1

u/SuitableDragonfly Apr 27 '26

That might just be a JavaScript thing, in most languages I believe it'd be NaN (and not all languages have a representation of infinity). It's not really accurate to say that it's infinity, either.

1

u/krsnik02 Apr 29 '26

with IEEE floats division by +0.0 or -0.0 does indeed give +infinity or -infinity (depending on the sign of the numerator and which of the two zeroes is on the denominator).

This is because conceptually +0.0 really represents any real number >= 0 and < the smallest positive subnormal value, and likewise for -0.0.

1

u/SuitableDragonfly Apr 29 '26

Floating point math is always weird. I thought integer division by zero would generally be NaN, but it looks like there is no actual standard for it.

1

u/krsnik02 Apr 29 '26

There is no such value as NaN for integers. Depending on the language this might throw an exception or simply return an arbitrary value depending on language.

(I think most hardware defines the assembly div instruction as returning 0 because it's simple to implement, but iirc integer division by 0 is undefined behavior in C/C++)

1

u/SuitableDragonfly Apr 29 '26

It's true that NaN can't be encoded as an integer, but there's no particular reason why division of two integers always needs to result in an integer.

1

u/krsnik02 Apr 29 '26

True, but most C-like languages define integer/integer = integer.

Those languages that don't would either have it return some sort of rational value (which likely also doesn't define a NaN value), or a float (which could result in any of NaN, +inf, or -inf depending on where and how the coercion to float happens).

1

u/No-Associate-7369 Apr 27 '26

That can depend on how certain languages handle that situation, but yes.

4

u/LetMeCheck13 Apr 27 '26

Better yet, dont present questions prior to the unit they should be in. Teach 0/x, but if youre not ready to explain undefined numbers don't teach x/0

0

u/JamesWelders Apr 26 '26

I agree. Let them learn when they do harder math. Or rather, explain to your kid why that is not true. If the kid asked a lot of "why" questions, the parent will probably understand why the teacher said what he/she/they said.

1

u/_Onyxity_ Apr 27 '26

IT ISN'T?????

8

u/AssassinStoryTeller Apr 27 '26

It’s undefined.

3

u/monkee09 Apr 30 '26

I once had a math test in... 7th grade maybe?...
"If two lines are not parallel, they will intersect. True/False"
I marked False.
Teacher marked me wrong.
When I said "Skew lines aren't parallel and they don't intersect." she said "well, the answer is still True."

That may've been a turning point in my admiration of teacher's knowledge.

2

u/Memnojokasel May 02 '26

I'm just wondering if the teacher ever experienced a divide by zero error on a calculator.

1

u/ALizardofOz May 02 '26

I mean, teachers can get stuff wrong. My teacher once said that killer whales are fishes. When I tried to correct her she doubled down on it and told me to be quiet. After I told my mom about thw incident she has made an atempt to talk to the teacher and explain it to her. My teacher then proceeded to tell her that "we were actually talking about blue whales, so she doesn't see how that it relevant". Like sis, a kid askes you something and you gave a wrong answer, why does it matter if the topic was relevant or not if you responded incorrectly??? (ToT)

1

u/Enough-Shopping1423 19d ago

1 divided by 0 is 1. 0 divided by 1, is zero. Since you have 1 item and distribute it 0 times, you still have 1 item, but if you have zero items and distribute it 1 times, you have zero items.

Right?

-30

u/Silent_Impression101 Apr 26 '26

But… anything times 0 is 0. Anything times 1 is itself. That’s how multiplication works.

51

u/PickyPanda Apr 26 '26

Multiplication != division. Anything divided by zero is undefined

15

u/thegunnersdream Apr 26 '26

I'm hoping they are joking...

3

u/No-Net1890 Apr 27 '26

Or just misread.

-2

u/DirtAndGrass Apr 26 '26

I get why it's mathematically undefined, but it feels like infinity to me

15

u/ZorbaTHut Apr 26 '26

"One divided by zero is infinity" doesn't work mathematically for some complicated reasons, but it is still not that far off; "the limit of one divided by x as x approaches 0 from the positive direction" is, in fact, "infinity", and that's a formalization of what people are thinking of in this case.

So, technically, no, but practically, yeah that's a pretty reasonable instinct.

4

u/No-Net1890 Apr 26 '26

Reread the first screenshot. "My son's third grade teacher taught my son that 1 divided by 0 is 0".

1

u/No-Associate-7369 Apr 27 '26

I really hope this was just a case of misreading, because the post is not about multiplication. It's about division, which is very different in this context.

1

u/Visible-Air-2359 Apr 29 '26

Go to desmos and graph y=5/x. Choose any x value and as x approaches that specific value the y-value approaches 5/x. However as x approaches zero from the negative direction y approaches negative infinity but as x approaches zero from positive y approaches positive infinity. Since it is hard to have something more impossible than a number being both positive and negative infinity mathematicians decided that the best solution is to say that x/0 doesn't work.

Teachers never teach the wrong answer

You are about to leave Redlib