Ask HN: Any good math jokes? | Hacker News Reader

Ask HN: Any good math jokes?

54 pointswhackedspinach131 comments

I'm trying to come up with a good math joke for our math team t-shirts. Last year we had "Know you limits, don't drink and derive." The shirt included a fuzzy graph.

I'm thinking about using an xkcd comic if the author gives me permission, but the images are somewhat small for t-shirts, so I might have to throw my own together anyways.

Got any good ideas?

View on HN

An engineer, a physicist, and a mathematician go to a conference together, and split a room in the hotel. They check in and go to sleep. The hotel is old (they couldn't afford anything better on professors' salaries), so the room is heated by a fireplace. A spark jumps out of the fire and catches the rug on fire. The engineer smells the smoke and wakes up. He jumps out of bed, sees the fire, and looks around. The first thing he sees is the ice bucket, so he takes it, fills it up from the sink, and throws the water on the fire. He drops the ice bucket next to the fireplace and goes back to bed.

The fire throws another spark, creating another fire. The physicist wakes up and sees the fire. He calculates that, given the size of the fire, and amount of oxygen needed to be displaced to put out a fire of said size, a glass of water will be sufficient. He fills up his water glass from the sink, and while running to the fire, throws the water at the fire at the exact distance from the fire that gets the water to the fire earliest, putting it out. He drops the glass next to the fireplace and goes to sleep.

The fire sparks once more, and the mathematician wakes up and sees the fire. He looks at the ice bucket and glass sitting next to the fireplace, says "Aha! A solution exists!", and goes back to bed.

It's a math joke, but not one suitable for t-shirts.

While we're at jokes not suitable for t-shirts:

A mathematician, an engineer and a physicist were travelling through Scotland when they saw a black sheep through the window of the train.

"Aha", says the engineer, "I see that Scottish sheep are black."

"Hmm", says the physician, "You mean that some Scottish sheep are black".

"Nonono", says the mathematician, "All we know is that there is at least one sheep in Scotland, and that at least one side of that one sheep is black."

An infinite number of mathematicians walk into a bar. The first one orders a beer. The second orders half a beer. The third, a quarter of a beer. The bartender says "You're all idiots", and pours two beers.

more: http://www.metafilter.com/76377/Two-mathematicians-walk-into...

Or its sibling: a genie grants both a mathematician and an engineer their greatest desire to be located at the end of the room given that each step they take towards it is half the distance than their last. The mathematician throws his arms up and yells "Impossible! I'll never reach it," and storms out of the room. The engineer just smiles and says to the genie, "I can get close enough."

So all but one have to share a glass? Seems unpractical.

They possibly have an infinite amount of time to share the glass around

Similar:

An infinite number of mathematicins walk into a bar. The first one orders a beer. The second orders half a beer. The third, a third of a beer. The bartender says, "what do you think I am, an idiot?" and kicks them all out.

An infinite number of mathematicians walk into a bar. The first one orders a beer. The second orders two beers. The third, three beers. The bartender says, "you guys owe me a twelfth of a beer."

(Explanation of that last one: http://en.wikipedia.org/wiki/1%2B2%2B3%2B4%2B... )

Q: What's purple and commutes? A: An Abelian grape.

Q: What's yellow and equivalent to the axiom of choice? A: Zorn's Lemon.

An engineer, a physicist, and a mathematician are riding on a train through the countryside. They look out the window and see a black cow. The engineer says, "Look, all the cows in this county are black!". The physicist sighs, and says "No, at least one cow in this county is black". The mathematician shakes his head sadly and says "There is at least one cow in this county that is black on at least one side".

Q: Why do Jewish mathematicians prefer complex analysis over many other fields of mathematics? A: because it is Cauchy'er.

I was never able to get this one to work out, but maybe someone smarter can do it. There was a line in a physics book I read once that said something like "electromagnetic fields can be described by anti-symmetric tensors of the second bank in four dimensions". I tried to set up a story involving Jewish industrialists who were elected to public office, and who owned farms, being attacked by a bunch of jew-hating males from a local choir, who also happened to work for the a small local bank, who had their farms surrounded and did coordinated attacks from North, South, East and West. The punch line was to be something "elected magnate's fields were defiled by anti-semitic tenors from the Second Bank in four directions". But I never could come up with a story that would end with that, and would bring to mind the corresponding physics so as to make that a groan-worth pun.

Below is my favorite math joke (copied it from http://www.onlinemathlearning.com/math-jokes-calculus.html as I didn't remember the exact wording). It's a bit long for a T-shirt, but a simple comic strip version could be made.

A constant function and e^x are walking on Broadway. Then suddenly the constant function sees a differential operator approaching and runs away. So e^x follows him and asks why the hurry. "Well, you see, there's this differential operator coming this way, and when we meet, he'll differentiate me and nothing will be left of me...!" "Ah," says ex, "he won't bother ME, I'm e to the x!" and he walks on. Of course he meets the differential operator after a short distance.

e^x: "Hi, I'm e^x"

diff.op.: "Hi, I'm d/dy"

I think I might have to add "Hi, I'm d/dy" to my mail signature collection. So random.

xkcd comics are already licensed under a Creative Commons Attribution-Noncommercial 2.5 license. That's probably all you need for a math team t-shirt.

upvoted it (at this time, it cancelled out a downvote).

No idea why it was initially downvoted, it's good information to point out. So long as you don't make money off the shirts, it's ok to use xkcd comics.

I saw that, but in the end some of the images are only about 700x400 px. At 200 ppi (which is what t shirts should be printed at, I guess), that just isn't a high enough resolution. And I'm not sure If I really want to make it larger since it will not look all that good.

You could always try contacting Randall and explain what you'd like to use the particular strip for to see if you could get a larger image.

Even if the current size was large enough, he would probably appreciate knowing about his work being printed like that as most people do.

You could load an xkcd comic into Inkscape or another vector graphics editor and trace it out by hand. It wouldn't take that long, and the end result would be a vector graphic that you could render to whatever size or resolution you need. (Creating a derivative work like this is allowed by the license.)

Not short enough for a shirt probably, but still good:

Three mathematicians and three accountants are traveling by train to a conference. At the station, the three accountants each buy tickets and watch as the three mathematicians buy only a single ticket.

"How are three people going to travel on only one ticket?" asks an accountant. "Watch and you'll see," answers an mathematician. They all board the train. The accountants take their respective seats but all three mathematicians cram into a restroom and close the door behind them.

Shortly after the train has departed, the conductor comes around collecting tickets. He knocks on the restroom door and says, "Ticket, please." The door opens just a crack and a single arm emerges with a ticket in hand. The conductor takes it and moves on.

The accountants saw this and agreed it was quite a clever idea. So after the conference, the accountants decide to copy the mathematicians on the return trip and save some money (being clever with money, and all). When they get to the station they buy a single ticket for the return trip.

To their astonishment, the mathematicians don't buy a ticket at all. "How are you going to travel without a ticket?" asked one perplexed accountant.

"Watch and you'll see," answered an mathematician. When they board the train the three accountants cram into a restroom and the three mathematicians cram into another one nearby. The train departs.

Shortly afterward, one of the mathematicians leaves his restroom and walks over to the restroom where the accountants are hiding. He knocks on the door and says, "Ticket, please."

my wife laughed. This one passes.

Math team: like being star quarterback, except you have to wait ten years before you can order the football team around.

If you do it in groups, you'd better be discrete.

(Related: Analysts do it continuously, and almost everywhere.)

Materials scientists do it with latex.

Biochemists do it with animals.

When civil engineers do it, the earth moves.

Software engineers do it all night long.

mathematicians do it in theory

(pretty old one)

Does that mean physicists do it in practice?

Mathematicians do it with LaTeX

Mathematicians do it in groups, rings and fields.

Q: Did you hear about the constipated mathematician?

A: He worked it out with a pencil.

This one always gets someone to cringe. I love it.

Alternately:

Q: How many mathematicians does it take to change a lightbulb?

A: One. The mathematician hands the lightbulb to two blondes, thereby reducing the problem to a previously-told joke.

There are two hard problems in computer science. Naming, cache invalidation, and off-by-one errors.

Make that 10 hard problems.

Similar to - There are 10 kinds on people. Those who understand binary and those who don't.

Every base is base 10.

http://cowbirdsinlove.com/43

I found this one particularly amusing :)

It took me a while to notice the aliens hands...

My favorite take on that one is more for compiler and embedded folks:

There are 1 kinds of people in this world. Those who know how to save bits. The rest are the default case.

A physicist, a biologist, and a mathematician see two people walk into an empty building. Five minutes later, 4 people walk out.

The physicist says "Obviously our initial observation was wrong."

The biologist says "They must have multiplied while they were in the building!"

The mathematician says "However you look at it, if two more people walk into that building it will be empty again."

An engineer, a physicist and a mathematician want to catch a lion. The engineer goes to Africa, builds a cage and traps the lion in it. The physicist builds a fence around Africa and pronounces: "I've trapped the lion". The mathematician builds a cage, climbs inside and pronounces: "I am outside".

In the fall of 2009, Mr. Apollinax discovered a method of simplifying mathematical expressions with profound, wide-ranging consequences. Mr. Apollinax has given it the name "indiscriminate cancellation". We see its power and reliability here:

  16/64 = 1/4 ;Cancel the 6
  19/95 = 1/5 ;Cancel the 9
  26/65 = 2/5 ;Cancel the 6
  49/98 = 4/8 ;Cancel the 9

Using his new tool, Mr. Apollinax quickly discovered and prove several surprising theorems, including the following:

  sin x / n = six ;Cancel the n

But the most celebrated application of this method of Mr. Apollinax is his amazing discovery of a deep, unexpected connection between the theories of complex numbers and trigonometry and the preparation of Mexican cuisine:

  sin / cos = tan ;definition of tangent
  i / co = ta ;cancel n and s
  i = taco ;multiply both sides by co

[Martin Gardner wrote a couple of April 1st columns about Mr. Apollinax. Worth checking out. Also, it's kind of a cool computer science problem to find number pairs like 16/64. I'll mention that if we generalize it to "abcd...x / bcd...xy = a/y", then there are seven nontrivial (where a,b,c,etc. aren't all the same digit) 3-digit pairs, including 484/847.]

Math problems? Call 1-800-[(10x)(13i)2]-[sin(xy)/2.362x].

(From http://www.math.ualberta.ca/~runde/jokes.html)

This is by far the best t-shirt candidate.

Math Overflow had a joke thread a while back: http://mathoverflow.net/questions/1083/do-good-math-jokes-ex...

An evil dictator locks up all the academics in his country in a time of war. As the war worsens the army platoon left guarding the detention facility is called away to the front, and leaves the academics unattended in their cells bottled water, canned food and no can openers. When the war is over and the dictatorship is collapsed, the detention facility is opened up. It's found that most of the humanities and social scientists have survived, having opened their cans by throwing them randomly at the walls until the cans broke open. The physicists had figured out the optimum angle at which to throw the can in order to reliably open it. Several mathematicians have suffered severe malnutrition, having successfully proven that "there exists a unique optimal throwing angle theta ..." The cell of a topologist was found empty, though a muffled screaming could be heard from one of his cans. A can opener is fetched, and the topologist is removed, covered in food, mumbling about an error in sign.

Years ago, three friends from Poland decided to visit relatives in the US they had not seen for decades. Since this was a once-in-a-lifetime trip, they did in grand style, on the Concorde.

Of course, there was trouble on the flight and of course the flight attendants asked if any of the passengers had experience with aircraft, and of course one of our friends did. He was taken to the cockpit to save the day, wherein he looked at the myriad dials and gauges and controls and turned to his friend and said... ...wait for it...

"I am but a simple Pole in a complex plane."

One for HN:

Q: Why did the two vectors start an internet-based company?

A: Because they thought they had a good dot product.

One for a t-shirt (stolen off the Internet):

Math problems? Call 1-800-[(10x)(13i)^2]-[sin(xy)/2.362x].

In terms of t-shirt type statements, I think this is the best I've read on here.

There's always the classic, 'Snakes ⊂ ℝ²'.

Can someone explain this one?

ℝ² is the Cartesian plane; it is a reference to the movie "Snakes On A Plane".

Q: What do you get when you cross a mosquito with a mountain climber?

A: You can't cross a vector with a scalar!

I'm sorry, how is a mosquito a vector?

mosquitos are vectors for disease (http://en.wikipedia.org/wiki/Vector_(biology))

A better version I heard changed 'mosquito' to 'mountain goat'. Since both characters are from the same domain, people start thinking about (more) reasonable solutions and get blindsided harder by the math reference!

Why did the chicken cross the Möbius strip?

To get to the same side.

This joke might be funnier if the answer is:

To get to the other side.

(The mathematicians will know that the chicken's quest will fail. Then they'll feel sorry for the chicken...)

But the non-mathematicians will JUST give you a weird look, rather than laughing and then giving you a weird look.

I don't know. A cliche can seem funny if you add a little twist, even if the twist is incomprehensible.

Surprised this isn't already here, pretty popular at my college:

I wish I was your derivative, so I could lie tangent to your curves.

And the companion bio-joke:

I wish I was mRNA polymerase, so I could unzip your genes.

Wow, best pickup line I've ever heard :-)

I've never heard them called "mRNA polymerases." RNA polymerase should do just fine.

In fact, wouldn't helicase do better?

Helicase is what unzips the genes, not RNA polymerase. RNA polymerase allows transcription (or creation of an mRNA molecule complementary to the given gene) to take place.

That one is so bad, because it doesn't work. Presumably the derivative is used to calculate a tangent line. However, a tangent line touches the curve only at one point, unless the curve is totally flat. Either way, this is not what you want. You want fuckin' Taylor series approximations. (They won't work on curves that aren't smooth, but that's all right, because those are the curves you want to touch anyway.)

Aww yeah.

Strictly speaking, the Taylor series won't even do what you're wanting them to do for smooth functions. (Consider the function e^{-1/x^2}, whose Taylor series is zero at the origin. In fact, given any sequence of numbers, you can cook up a smooth function which has that sequence as the coefficients of its Taylor series at zero.) If you want the Taylor series to agree with the function in an entire neighborhood of a point, you want the function to be real (or complex) analytic (at least in a neighborhood of that point).

That's true. I was careful to say "They won't work on curves that aren't smooth", which doesn't mean "They will work on all curves that are smooth", so I think what I said is still correct.

And as long as we are going for perfect rigor, the function you describe is undefined at x=0; you have to make it piecewise and say "if x=0, then this function is 0". (And I could say something about "you want natural curves, not this artificial pieced-together stuff.")

Also, I believe the Taylor series for that function is well-defined and accurate at all points other than x=0, so you can just pick one of those points. Are there smooth functions whose Taylor series are wrong everywhere? I doubt it. And one might argue that it's pretty problematic that, e.g., with the function "0 if x≤0, e^{-1/x^2} if x>0", a Taylor series at any positive point will be wrong for all negative numbers, and a Taylor series at any nonnegative point will be wrong for all positive numbers... well, I dunno, touching half of the entire range of a curve is still a lot (an infinite amount, in fact).

One could imagine a bunch of functions pieced together to make a smooth function (e.g. "e^{-1/x^2} * e^{-1/(x-1)^2} for 0<x<1, e^{-1/(x-1)^2} * e^{-1/(x-2)^2} for 1<x<2, ...") whose Taylor series are all accurate only over a small, finite domain. I guess that kinda answers my question. But at this point I would apply the "natural curves" objection. I wonder, are there smooth non-piecewise functions whose Taylor series are all wrong like that? (Absolute value is a piecewise function, so I'd probably reject anything with absolute value.)

Not sure you can copy it, but I've always wanted this shirt (not sure why, but I found it hilarious):

http://www.thinkgeek.com/tshirts-apparel/unisex/generic/60f5...

It reads:

2 + 2 = 5

(For extremely large values of 2)

My all time favorite is "Find x": http://www.ximnet.com.my/thelab/images/upload/findX.jpg

"Be Rational" and "Get Real" is pretty good too: http://media.photobucket.com/image/rational/CocaC0la99/be-ra...

"Leibnitz > Newton" could provoke a fist fight. This would be hilarious to see.

edit: Better than xkcd, depending on your sense of humor (i.e., whether you have one) is smbc-comics.com. Dunno how he licenses his stuff though.

An old one :

Why do mathematician mistake Halloween for Christmas ?

Because to them, 31oct = 25dec

Front: (a^n) + (b^n) = (c^n) true only when n <= 2 if a,b,c are positive integers.

Back: I have discovered a truly marvelous proof but this shirt is too too narrow to contain it

Or, why I spent ten years in an attic on a silly proof.

It was something like ten years Andrew Wiles spent on it, wasn't it?

Here's one but it's in French.

"Qui se cache derrière le nombre 1.09861228866811... ?" "Hélène de Troie. (ln 3)"

There's always the old donut and coffee mug being topologically equivalent.

Or the integral of e^X (write it down)

Or Pi telling i to be real and i telling Pi to be rational.

Or your mom so ugly I had to use the Fourier transform to solve her (just made that one up, probably doesn't make any sense ;p)

+1 for Pi telling i to be real and i telling Pi to be rational

http://roflcopter.pl/math-jokes.jpg

What's the square root of 69? Eight something.

Good math jokes split into two groups: either they're funny, or they make you feel clever for understanding them, I think. The latter are more fun.

Simple Level:

What's special about plants in the maths common room?

They have square roots.

More Educated:

Why can't you plant wheat in the integers mod 6?

Because 6 isn't prime!

"Life is complex is because it has both real and imaginary components."

Cannot recall the source.

I love the people in this thread giving jokes that are aimed at five year olds, rather than a math team who's previous joke was "don't drive and derive".

Q: what did the zero say to the eight? A: nice belt!

An all time favorite of mine! (:

A friend of mine once claimed that a specific celebrity couple had their ages as 88 years and 44 years respectively. All others said that they knew the age difference was big for this couple, but it couldn't be that big! Some more probing and my friend blurted "I remember exactly that when they got married, they were 44 and 22 respectively".

Question:Whatz a PJ ? Answer: Obviously "a poor joke" Question: Whatz a (P + iJ)? Answer: "complex poor joke" But why don't people laugh on a "complex poor joke"? Bcoz the joke part of it is imaginary.

http://www.akhilesh.in/life/fun/jokes/pj0061AComplexPJ.php

http://en.wikipedia.org/wiki/Math_jokes

Love this one : http://spikedmath.com/325.html

I'd recommend digging through the spiked math "best of" list and looking for something that suits the math team's fancy.

(x,why?) can also be quite entertaining.

There are 10 kinds of methematicians, those that count in ternary and those that don't.

(Not many people, even mathematicians and computer scientists, get that one. I think it's better than the usual crap binary non-joke, and wish I could remember where I heard it)

There are 10 kinds of people in the world, those who understand binary and those who don't.

whats a chefs favorite triangle? isauceles

how did the abelian group get to work? it commuted

why do addition and the integers carpool? because theyre a commutative group

At a party, all mathematical functions are having fun, except the exponential, which is standing lonely in one corner. Another function approaches it and says: why don't you integrate? And it: oh, because it's the same...

Not sure if that can fit on the t-shirt, but here are couple of ideas

http://farm3.static.flickr.com/2174/2268237733_cda4a1dbb3.jp...

http://geektech.geektech.netdna-cdn.com/wp-content/uploads/2...

(these are 'captchas' that require you to solve a problem)

Also, liked these (unrelated to maths):

http://geektechnica.com/2010/06/10-craziest-captchas-out-the...

What is the par value of a zero-coupon bond with no maturity?

Pee dollars!

Did you see the SNL segment on options? It was put-call parody!

Complex analysis: it's as easy as pulling out an i.

Analysis, something, something. Balls! (I haven't quite finished that one).

What do you get when you cross an elephant and a banana?

(Elephant)(banana)sin(theta)

Maybe you could fit just the punchline on a T-shirt:

A sociologist, a physicist, and a mathematician are given 100 ft of fence and asked to enclose the greatest area.

-The sociologist makes a square. -The physicist makes a circle and says he can PROVE it's the best answer. Take that, mathematician! -The mathematician knocks off all but a few fence-links, wraps the fence around himself, and says "Define the outside of the fence to be the ground which contains me..."

(Say the punchline in a smarmy, nasal voice.)

Physicist, pastor and mathematician on the top of a skyscraper. They are asked to jump precisely into the swimming pool on the ground. Phsycist calculates wind, distance, perspective, jumps and lands in the pool. Pastor meditates, prays, focuses, jumps and lands in the pool. Mathematician calculates a beautiful parabel, jumps and goes straight up to the sky. What happend? Oh well, he made a sign flaw :)

An engineer and a mathematician went out for a drink. On the other side of the room, they spotted a gorgeous woman.

"I wish I could work up the courage to talk to her," said the shy mathematician.

"No problem," said the engineer. "Just walk halfway over to her, take a sip of beer, then walk halfway again, and do that over and over until you're next to her.

"But then I'll NEVER get there," said the mathematician.

http://www.wolframalpha.com/input/?i=Tell+me+a+joke.

A sahillavingia original:

Q: What did the difficult cartesian-coordinate system tell his problem-solver when he wanted to visit Antartica?

A: You should go polar!

i 8 √-1 Πs. (I ate imaginary pies?) You might have to play around with it, but I hope it's a good start. :)

If you want to incorporate ideas from xkcd without using any of the published comics, you could come up with your own nerd snipe and put it on the front of your shirt. Then put something on the back like "You've been nerd-sniped!"

Make sure to hang out near busy streets and train tracks when you wear it.

Don't know whether this fits as a joke, but:

    exp(I*pi) + 1 = 0

Thats not a joke its an import mathematical identity.

http://en.wikipedia.org/wiki/Euler%27s_identity

"Spherical bastard: Someone who's a bastards from every viewpoint"

http://scienceworld.wolfram.com/biography/Zwicky.html

Not sure where I heard this ...

Biology is really Chemistry. Chemistry is really Physics. Physics is really Maths. and Maths is really hard.

Its not a joke but a series of punny things crammed into a catchy song:

  http://www.youtube.com/watch?v=BipvGD-LCjU

http://www.math.ualberta.ca/~runde/jokes.html

Q: What the integral of (1/cabin)dCabin?

A: Beach Hut

(Log Cabin + C)

[Maybe just the formula would fit on a T Shirt, and you get to explain it to people who ask?]

Q: Integral dCabin/Cabin?

A: natural log cabin

I always heard "houseboat".

Eat the pie, I; my new swan is nothing.

friend had a shirt that said

"be there or c squared minus a squared"

lol

I've always wanted a t shirt that said "I love LAMP" with a picture of a computer on it.

A mathematician got something stuck up his ass. He worked it out with a pencil.

assume: x = y then: xx = xy and then: xx - yy = xy - yy factor: (x+y)(x-y) = y (x-y) cancel: x+y = y replace: x + x = x simplify: 2 * x = x therefore: 2 = 1 QED

According to statistics, a normal person has one breast and one testicle...

I object! The average person has less than one breast and less than one testicle.

I object again! Statistics say there are slightly less men than women in the states. Therefore, the average person has more than one breast and less than one testicle.

http://en.wikipedia.org/wiki/Demographics_of_the_United_Stat...

I object yet again! Mastectomies surely offset the breast:testicle ratio to a statistically-significantly degree!

Q) What did the Zen Buddhist say to the hot dog vendor?

A) Make me One with everything.

Not really a joke, but possibly good for a t-shirt:

"sec(C)"

What about:

"I'm too 1/cos(C) for my shirt"

here's one from the last decade.

Q. what did the math teacher say when she saw tennis star monica seles?

A. isosceles

Why was 6 afraid of 7?

Because 7 8 9!

(7 ate 9)

I like how you explained it just in case.

http://www.smbc-comics.com/index.php?db=comics&id=2040

I think you mean (ate 7 9). Don't feel bad, infix notation can creep up even on experienced Lisp programmers.

Those brackets were not for Lisp! God! They are also used for English.

I don't get it. Why did 7 eat 362,880?

Real analysis takes balls.

Let epsilon < 0

Let ε < 0.

assume: x = y then: x^2 = y^2

   Math Club

then put a picture of a hot chick, and some MDMA

then Transcendental Numbers

There are three types of mathematicians. Those who can add and those who can't.

1i + 1i = 2i

Cannot have Magic without the i

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