Math bloopers heard in math classes
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Math bloopers heard in math classes
I was prompted to start this with a student mentioning the "standard devastation" on a paper I had to grade because of a lazy teacher giving papers to other students to grade.
Re: Math bloopers heard in math classes
AP Stat teacher in high school:
1/3 + 1/3 + 1/3 does NOT equal 1!!!
This was also the same teacher who tried to say we couldn't use calculus to prove our answers (probably because she didn't know calculus, she decided on teaching math while in community college) Needless to say it was a frustrating class.
1/3 + 1/3 + 1/3 does NOT equal 1!!!
This was also the same teacher who tried to say we couldn't use calculus to prove our answers (probably because she didn't know calculus, she decided on teaching math while in community college) Needless to say it was a frustrating class.
 3.14159265...
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Re: Math bloopers heard in math classes
Cos = Pussy (Persian, Arabic, Hebrew)
TrigHilarity.
TrigHilarity.
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Re: Math bloopers heard in math classes
3.14159265... wrote:Cos = Pussy (Persian, Arabic, Hebrew)
TrigHilarity.
Actually, it's more like "Koos".
A TA in a calculus class told us about a test he saw once asking for the limit as x approached zero of: e^{lan(x)}/x (he didn't know which course it was, he joked maybe it was calculus for movie appreciation) and the guy decided to use L'Hopital's rule. Of course, he again got e^{lan(x)}/x. So he used L'Hopital again. And then once more. Eventually he wrote "I don't have time to finish the proof but it's obvious this would work".
I doubt it's a real story but it's funny.
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Re: Math bloopers heard in math classes
Is that lan(x) the natural logarithm of x? If so, that's pretty funny.
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Re: Math bloopers heard in math classes
Not in persian or Arabic, but yes in Hebrew.Actually, it's more like "Koos".
Learning to say "What is this?" in French was also hillarious to that end.
"The best times in life are the ones when you can genuinely add a "Bwa" to your "ha"" Chris Hastings
Re: Math bloopers heard in math classes
Lecturer: "...and now we can find this value using Pythagoras..."
Student (shouts out): "What's Pythagoras?"
Lecturer: (stops dead)
Student (shouts out): "What's Pythagoras?"
Lecturer: (stops dead)
This is a placeholder until I think of something more creative to put here.

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Re: Math bloopers heard in math classes
Robin S wrote:Lecturer: "...and now we can find this value using Pythagoras..."
Student (shouts out): "What's Pythagoras?"
Lecturer: (stops dead)
Wait, the lecturer DIED? Shit, I'll have to try this one sometime.
Re: Math bloopers heard in math classes
It was hard to tell for the first few seconds, but fortunately he recovered control of his facial expressions and sputtered something along the lines of "Excuse me? What is Pythagoras?"
You had to be there, really.
You had to be there, really.
This is a placeholder until I think of something more creative to put here.
Re: Math bloopers heard in math classes
Pathway wrote:Is that lan(x) the natural logarithm of x? If so, that's pretty funny.
Yes, it means log_{e}(x). I thought that was obvious with lan... That was pretty funny.
Mighty Jalapeno: "See, Zohar agrees, and he's nice to people."
SecondTalon: "Still better looking than Jesus."
Not how I say my name
SecondTalon: "Still better looking than Jesus."
Not how I say my name
Re: Math bloopers heard in math classes
Zohar wrote:
A TA in a calculus class told us about a test he saw once asking for the limit as x approached zero of: e^{lan(x)}/x (he didn't know which course it was, he joked maybe it was calculus for movie appreciation) and the guy decided to use L'Hopital's rule. Of course, he again got e^{lan(x)}/x. So he used L'Hopital again. And then once more. Eventually he wrote "I don't have time to finish the proof but it's obvious this would work".
I doubt it's a real story but it's funny.
I would definitely use that as a question if I were to make an elementary calculus test.
Evaluate lim_{x>0+} e^{ln(x)}/x
Hint: use L'Hôpital, if necessary several times.
Would have been fun to see how the students would react.
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Re: Math bloopers heard in math classes
Isn't e^{ln(x)} just x, though? That'd make things a lot easier.
Re: Math bloopers heard in math classes
scowdich wrote:Isn't e^{ln(x)} just x, though? That'd make things a lot easier.
Exactly, that's the point. The question is extremely easy if you stand back and think about it for a second, but it will catch students who have been just "following the rules" the whole time.
Re: Math bloopers heard in math classes
GBog wrote:I would definitely use that as a question if I were to make an elementary calculus test.
Evaluate lim_{x>0+} e^{ln(x)}/x
Hint: use L'Hôpital, if necessary several times.
Would have been fun to see how the students would react.
I'm going to do that sometime. Promise.
BTW, your avatar is wrong .
Now these points of data make a beautiful line.
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Re: Math bloopers heard in math classes
Govalant wrote:
BTW, your avatar is wrong .
I think it's just using the lazy version of summation notation where "n=0" really means "n is the smallest positive integer that makes sense. I tend to use this (usually accidentally) multiple times each semester. It saves time when writing tests... Proofread? what's that?
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Re: Math bloopers heard in math classes
The worst math teacher I ever had (first day of class):a meter is a different length in the evening then it is in the morning
Me:*headache*
Teacher:this is because in the evening the meter stick is warmer, and expands slightly.
Me:<explanation of how the meter is defined as the distance light goes in 1/299792458 of a second, and that the meter stick corresponds to that distance, not vice versa>
Teacher:<stunned silence of someone defying him><30 minute rant about how the desk is the perfect student>
He eventually flunked me despite getting every question right on his tests.
Me:*headache*
Teacher:this is because in the evening the meter stick is warmer, and expands slightly.
Me:<explanation of how the meter is defined as the distance light goes in 1/299792458 of a second, and that the meter stick corresponds to that distance, not vice versa>
Teacher:<stunned silence of someone defying him><30 minute rant about how the desk is the perfect student>
He eventually flunked me despite getting every question right on his tests.
If four times five is twelve, and four times six is thirteen, and four times seven is fourteen, what base is next? And more importantly, who is doing the calculation?
Re: Math bloopers heard in math classes
Govalant wrote:BTW, your avatar is wrong .
Damn, thanks for notifying me. (Fixed now.)
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Re: Math bloopers heard in math classes
MrHackman don't be a smart ass. Ever. They suck.
If you want to correct your teacher, do so after the glass, unless it is something you didn't understand. Specially if it is the first day!
Teachers and School are not made for students who know the material to be studied, they are made for the other people.
Your information is completely irrelevant to half the kids, but expanding metal helps with opening cans and thus not irrelevant.
My point, don't be a smart ass, seriously. There is a kid in my class who thinks he is smart. We all hate him. Don't be that guy. It won't get you laid, nor will it make you smarter.
If you want to correct your teacher, do so after the glass, unless it is something you didn't understand. Specially if it is the first day!
Teachers and School are not made for students who know the material to be studied, they are made for the other people.
Your information is completely irrelevant to half the kids, but expanding metal helps with opening cans and thus not irrelevant.
My point, don't be a smart ass, seriously. There is a kid in my class who thinks he is smart. We all hate him. Don't be that guy. It won't get you laid, nor will it make you smarter.
"The best times in life are the ones when you can genuinely add a "Bwa" to your "ha"" Chris Hastings
Re: Math bloopers heard in math classes
This would apply if the teacher just missed an important point or made a trivial error, which is different to saying something completely incorrect.3.14159265... wrote:My point, don't be a smart ass, seriously.
Re: Math bloopers heard in math classes
MrHackman wrote:The worst math teacher I ever had (first day of class):a meter is a different length in the evening then it is in the morning
Me:*headache*
Teacher:this is because in the evening the meter stick is warmer, and expands slightly.
Me:<explanation of how the meter is defined as the distance light goes in 1/299792458 of a second, and that the meter stick corresponds to that distance, not vice versa>
Teacher:<stunned silence of someone defying him><30 minute rant about how the desk is the perfect student>
He eventually flunked me despite getting every question right on his tests.
The meter can be defined in a lot of ways, and the length of the meter stick in France used to be the definition, up until the 90's I think. So what your teacher said was right, just the wrong timeline. Depending on how old you are.
Re: Math bloopers heard in math classes
aguacate wrote:The meter can be defined in a lot of ways, and the length of the meter stick in France used to be the definition, up until the 90's I think. So what your teacher said was right, just the wrong timeline. Depending on how old you are.
It would still be wrong even when they used the International Prototype metre (up until 1960). The length was defined as the distance between two lines on the bar, measured at 0°C. I think it's reasonable enough that if you're going for a fairly precise definition, you're not just going to leave your reference lying around in the sun.
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Re: Math bloopers heard in math classes
It does apply.
High school is not supposed to be rigourous. I understand that you think it should be. However a curriculum that is that scientifically rigorous will not produce a good student body.
Not all people think and want to learn the same way as those on XKCD.
High school is not supposed to be rigourous. I understand that you think it should be. However a curriculum that is that scientifically rigorous will not produce a good student body.
Not all people think and want to learn the same way as those on XKCD.
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Re: Math bloopers heard in math classes
3.14159265... wrote:It does apply.
High school is not supposed to be rigourous. I understand that you think it should be. However a curriculum that is that scientifically rigorous will not produce a good student body.
Not all people think and want to learn the same way as those on XKCD.
No. I doesn't. You fail.
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Re: Math bloopers heard in math classes
Alright let's take the approach that we should scrutinize all teachers because obviously they must be brilliant and have learned the material from University perfectly, because of course that is why they choose not to go on.
I see that you guys get everything right all the time, and that no sciencenazis don't exist that can even out scrutinize you. But we should reward them for trying to make the teacher look stupid, and then smirking.
Maybe I am saying this stuff from experience, maybe I was that smartass, and then realized it is much better to be the guy/gal that wants to learn.
I see that you guys get everything right all the time, and that no sciencenazis don't exist that can even out scrutinize you. But we should reward them for trying to make the teacher look stupid, and then smirking.
Maybe I am saying this stuff from experience, maybe I was that smartass, and then realized it is much better to be the guy/gal that wants to learn.
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Re: Math bloopers heard in math classes
Less serious debate, more funny please!
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Re: Math bloopers heard in math classes
the tree wrote:This would apply if the teacher just missed an important point or made a trivial error, which is different to saying something completely incorrect.3.14159265... wrote:My point, don't be a smart ass, seriously.
Second that. (Me teaching complex analysis and the like myself)
Finite simple group of order two
...
You're the upper bound in the chains of my heart
You're my Axiom of Choice, you know it's true
...
by The Klein Four Group
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You're the upper bound in the chains of my heart
You're my Axiom of Choice, you know it's true
...
by The Klein Four Group

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Re: Math bloopers heard in math classes
3.14159265... wrote:Alright let's take the approach that we should scrutinize all teachers because obviously they must be brilliant and have learned the material from University perfectly, because of course that is why they choose not to go on.
I see that you guys get everything right all the time, and that no sciencenazis don't exist that can even out scrutinize you. But we should reward them for trying to make the teacher look stupid, and then smirking.
Maybe I am saying this stuff from experience, maybe I was that smartass, and then realized it is much better to be the guy/gal that wants to learn.
There's a big difference between "all teachers...must be brilliant and have learned the material from University perfectly" and saying something as stupid as "the meter is not the same length in the morning and in the evening"
Second point: the teacher should be happy to be corrected and to have learnde something from one of the students. It happend to me that students corrected me about something, so I'm speaaking from experience myself.
Finite simple group of order two
...
You're the upper bound in the chains of my heart
You're my Axiom of Choice, you know it's true
...
by The Klein Four Group
...
You're the upper bound in the chains of my heart
You're my Axiom of Choice, you know it's true
...
by The Klein Four Group
Re: Math bloopers heard in math classes
3.14159265... wrote:My point, don't be a smart ass, seriously. There is a kid in my class who thinks he is smart. We all hate him. Don't be that guy. It won't get you laid, nor will it make you smarter.
Same here. This guy we hate tries to correct the teacher(s) on meaningless stuff, and most times, he is wrong. He also bothers the shit out of everyone because he asks stupid questions that are going to be explained in a few minutes.
Anyway, I don't think I have funny story, but my math teacher screwed up pretty often.
Once, when solving some logarithmic problem she calculated some constants like log_{2}3 and used them in the calculation (which was 20 lines long). She got 23,28 when the answer was 24 and could be solved in 3 lines.
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Re: Math bloopers heard in math classes
Before you read this one, solve this problem:
x=3^{2}
x=3^{2}
Spoiler:
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Re: Math bloopers heard in math classes
I can see people getting that wrong.
I was in a number theory course, when the teacher put up the formula for primes under n (n/log(n)). Just to make sure, I ask, "Base e right?"
He says "No, base 10."
Ummm
"Are you sure? What about 10? That formula gives 10 primes under 10"
"It's approximate"
"Well, yeah, but why 10? Why not four? Or two? Or e?"
"But it's 10."
This resulted in the TA (19 year old college student who was completely awesome and kicked our 1415 year old asses at chess) coming up and talking with him, several books being brought out, and in general a 1/2 hour break. (A good thing as no one liked the teacher. It was CTY and basically lecture format, which isn't fun 8 hours a day. Not his fault.). (Also, he pronounced integer as inTEger). The teacher would not admit that what he remembered was wrong, so that evening, at the 2 hour study hall where the TA was around instead of the teacher, he made sure that we understood that he was wrong.
I was in a number theory course, when the teacher put up the formula for primes under n (n/log(n)). Just to make sure, I ask, "Base e right?"
He says "No, base 10."
Ummm
"Are you sure? What about 10? That formula gives 10 primes under 10"
"It's approximate"
"Well, yeah, but why 10? Why not four? Or two? Or e?"
"But it's 10."
This resulted in the TA (19 year old college student who was completely awesome and kicked our 1415 year old asses at chess) coming up and talking with him, several books being brought out, and in general a 1/2 hour break. (A good thing as no one liked the teacher. It was CTY and basically lecture format, which isn't fun 8 hours a day. Not his fault.). (Also, he pronounced integer as inTEger). The teacher would not admit that what he remembered was wrong, so that evening, at the 2 hour study hall where the TA was around instead of the teacher, he made sure that we understood that he was wrong.
Wait. With a SPOON?!
Re: Math bloopers heard in math classes
Not exactly heard...but I will from time to time be working some long trig problem on the board and writing rather quickly when there will be a few chuckles and giggles from the class...looking back at my work I have sadly written sex in place of sec x. ( Hmm... it's much funnier when it happens in a rather dry spot in a math class full of high school students than written out here.)
Re: Math bloopers heard in math classes
.
Last edited by Durandal on Wed Jul 08, 2009 4:50 am UTC, edited 2 times in total.
Re: Math bloopers heard in math classes
How would you say sec(x) out loud? My horrible EstuaryEnglish accent means I usually pronounce it as 'sex' anyway.
I still can't help internally giggling at graphs that look in the slightest bit rude.
I still can't help internally giggling at graphs that look in the slightest bit rude.
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Re: Math bloopers heard in math classes
the tree wrote:How would you say sec(x) out loud? My horrible EstuaryEnglish accent means I usually pronounce it as 'sex' anyway.
"Secant ex"?
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Re: Math bloopers heard in math classes
I've got two:
1) A lecturer was talking about applications of different numeral systems (in this case, ternary) and after some calculations ended up with like
3(f(x))

9(g(x))
which he obviously then cancelled down to f(x)/3g(x).
and someone said "hang on, where did the third come from?" and the lecturer said "right ok," returning to the board while he processed the enquiry and then stopped and had no choice but to say "well... three over nine ... is one over three."
The look on his face was priceless!
2) Secondly, not exactly a blooper, but still funny: Back in school a friend of mine, who was probably the best in the class, asked the teacher for assistance, and for a joke he'd cancelled "sin(x)/x" to just "sin", and when she noticed she shrieked "But this is MEANINGLESS!!"
1) A lecturer was talking about applications of different numeral systems (in this case, ternary) and after some calculations ended up with like
3(f(x))

9(g(x))
which he obviously then cancelled down to f(x)/3g(x).
and someone said "hang on, where did the third come from?" and the lecturer said "right ok," returning to the board while he processed the enquiry and then stopped and had no choice but to say "well... three over nine ... is one over three."
The look on his face was priceless!
2) Secondly, not exactly a blooper, but still funny: Back in school a friend of mine, who was probably the best in the class, asked the teacher for assistance, and for a joke he'd cancelled "sin(x)/x" to just "sin", and when she noticed she shrieked "But this is MEANINGLESS!!"
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Re: Math bloopers heard in math classes
Durandal wrote:mikegoo wrote:Not exactly heard...but I will from time to time be working some long trig problem on the board and writing rather quickly when there will be a few chuckles and giggles from the class...looking back at my work I have sadly written sex in place of sec x. ( Hmm... it's much funnier when it happens in a rather dry spot in a math class full of high school students than written out here.)
I did that on a test once. Eight times.
My teacher then introduced to topic of Freudian slips to me.
ahh yes, the freudian slap. when you say one thing but you mean your mother.
in ur beanz makin u eveel
Re: Math bloopers heard in math classes
Haha, I definitely PENIS what you mean.
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Re: Math bloopers heard in math classes
That reminds me. What is lim_{n>oo} (sin x)/n?triangl wrote:2) Secondly, not exactly a blooper, but still funny: Back in school a friend of mine, who was probably the best in the class, asked the teacher for assistance, and for a joke he'd cancelled "sin(x)/x" to just "sin", and when she noticed she shrieked "But this is MEANINGLESS!!"
Spoiler:
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Re: Math bloopers heard in math classes
triangl wrote:I've got two:
1) A lecturer was talking about applications of different numeral systems (in this case, ternary) and after some calculations ended up with like
3(f(x))

9(g(x))
which he obviously then cancelled down to f(x)/3g(x).
and someone said "hang on, where did the third come from?" and the lecturer said "right ok," returning to the board while he processed the enquiry and then stopped and had no choice but to say "well... three over nine ... is one over three."
The look on his face was priceless!
I have no idea what happened here, I can't see a problem with the answer of the admittal. Doesn't ternary mean you can only have 0,1,2 though? If that's the point, I don't get it.

My maths teachers made plenty of mistakes over the years, but none of them were notable enough to remember, and they usually just added the "Yeah, that was a test, haha, I'm so funny" excuse when someone pointed them out.
Funniest thing in maths class was the first class we had with an American exchange teacher and whenever she said "Pencil Bag" instead of "Pencil Case" everyone giggled.
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Re: Math bloopers heard in math classes
most competent teachers, when corrected, just say "vigilance test" and get back to the material. its not that big a deal. there's no reason to start a hate feud with someone over something like that.
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