A math professor is talking to her little brother who just started his first year of graduate school in mathematics.
"What's your favorite thing about mathematics?" the brother wants to know.
"Knot theory."
"Yeah, me neither." 

A visitor at the Royal Tyrell Museum asks a museum employee: "Can you tell me how old the skeleton of that T-Rex is?"
"It is precisely 60 million and three years, two months, and eighteen days old."
"How can you know that with such precision?!"
"Well, when I started working here, one of the scientists told me that the skeleton was 60 million years old - and that was precisely three years, two months, and eighteen days ago..."

The math professor's six-year-old son knocks at the door of his father's study.
"Daddy", he says. "I need help with a math problem I couldn't do at school."
"Sure", the father says and smiles. "Just tell me what's bothering you."
"Well, it's a really hard problem: There are four ducks swimming in a pond, when two more ducks come and join them. How many ducks are now swimming in the pond?
The professor stares at his son with disbelief: "You couldn't do that?! All you need to know is that 4 + 2 = 6!"
"Do you think, I'm stupid?! Of course, I know that 4 + 2 = 6. But what does this have to do with ducks!?"

"What is Pi?"
A mathematician: "Pi is the ratio of the circumference of a circle to its diameter."
A computer programmer: "Pi is 3.141592653589 in double precision."
A physicist: "Pi is 3.14159 plus or minus 0.000005."
An engineer: "Pi is about 22/7."
A nutritionist: "Pie is a healthy and delicious dessert!"

A mathematician and a stock broker go to the races to bet on horses. The broker suggests a bet of $10,000. That's too much for the mathematician's taste: First, he wants to understand the rules, have a look at the horses, etc.
"Don't worry", the broker says. "I know an empirical algorithm that allows me to find the number of the winning horse with absolute certainty."
This does not convince the mathematician.
"You are too theoretical!" the broker exclaims and puts his $10,000 on a horse.
The horse comes in first - making the broker even richer than he already is. The mathematician is baffled.
"What is your algorithm?" he wants to know.
"It's rather easy. I have two children, three and five years old. I add up their ages and bet on that number."
"But three plus five is eight - and that horse had number nine!"
"I told you that you're too theoretical! Didn't I just experimentally prove that my calculation is correct?!"

When the logician's little son refused again to eat his vegetables for dinner, the father threatened him: "If you don't eat your vegies, you won't get any ice-cream!"
The son, frightened at the prospect of not having his favorite dessert, quickly finished his vegetables.

Four friends have been doing really well in their calculus class: they have been getting top grades for their homework and on the midterm. So, when it's time for the final, they decide not to study on the weekend before, but to drive to another friend's birthday party in another city - even though the exam is scheduled for Monday morning. As it happens, they drink too much at the party, and on Monday morning, they are all hung over and oversleep. When they finally arrive on campus, the exam is already over.
They go to the professor's office and offer him an explanation: "We went to our friend's birthday party, and when we were driving back home very early on Monday morning, we suddenly had a flat tire. We had no spare one, and since we were driving on backroads, it took hours until we got help."
The professor nods sympathetically and says: "I see that it was not your fault. I will allow you to make up for the missed exam tomorrow morning."
When they arrive early on Tuesday morning, the students are put by the professor in a large lecture hall and are seated so far apart from each other that, even if they tried, they had no chance to cheat. The exam booklets are already in place, and confidently, the students start writing.
The first question - five points out of one hundred - is a simple exercise in integration, and all four finish it within ten minutes.
When the first of them has completed the problem, he turns over the page of the exam booklet and reads on the next one:

A stats professor plans to travel to a conference by plane. When he passes the security check, they discover a bomb in his carry-on-baggage. Of course, he is hauled off immediately for interrogation.
"I don't understand it!" the interrogating officer exclaims. "You're an accomplished professional, a caring family man, a pilar of your parish - and now you want to destroy that all by blowing up an airplane!"
"Sorry", the professor interrupts him. "I had never intended to blow up the plane."
"So, for what reason else did you try to bring a bomb on board?!"
"Let me explain. Statistics shows that the probability of a bomb being on an airplane is 1/1000. That's quite high if you think about it - so high that I wouldn't have any peace of mind on a flight."
"And what does this have to do with you bringing a bomb on board of a plane?"
"You see, since the probability of one bomb being on my plane is 1/1000, the chance that there are two bombs is 1/1000000. If I already bring one, the chance of another bomb being around is actually 1/1000000, and I am much safer..."

At a press conference held at the White House, president George W. Bush accused mathematicians and computer scientists in the U.S. of misusing classroom authority to promote a Democratic agenda. "Every math or CS department offers an introduction to AlGore-ithms", the president complained. "But not a single one teaches GeorgeBush-ithms..."

Q: How do you call a one-sided nudie bar?
A: A Moebius strip club.

"Divide fourteen sugar cubes into three cups of coffee so that each cup has an odd number of sugar cubes in it."
"That's easy: one, one, and twelve."
"But twelve isn't odd!"
"It's an odd number of cubes to put in a cup of coffee..."

Q: How can you tell that a mathematician is extroverted?
A: When talking to you, he looks at your shoes instead of at his.

When the math professor's wife returns home from work, she finds an envelope on the living room table. She opens it and finds a letter from her husband:

My dearest wife,

We have been married for nearly thirty years, and I still love you as much as on the day I proposed. You must realize, however, that you are now 54 years old and no longer able to satisfy certain needs I still have. I very much hope that you are not hurt to learn that, while you're reading this, I'm in a hotel room with an 18-year-old freshman girl from my calculus class. I'll be home before midnight.

Your husband, who will never stop loving you.

When the professor returns from the hotel shortly before midnight, he also finds an envelope in the living room. He opens it and reads:

My beloved husband,

You may recall that you, too, are 54 years old and no longer able to satisfy certain needs I still have. I thus hope that you are not hurt to learn that, while your're reading this, I am in a hotel room with the 18-year-old pool boy.

Your loving wife.

P.S. As a mathematician, you are certainly aware of the fact that 18 goes into 54 many more times than 54 goes into 18. Therefore, don't stay up and wait for me.

Q: What does the little mermaid wear?
A: An algae-bra.

A mathematical biologist spends his vacation hiking in the Scottish highlands. One day, he encounters a shepherd with a large herd of sheep. One of these cuddly, woolly animals would make a great pet, he thinks...
"How much for one of your sheep?" he asks the shepherd.
"They aren't for sale", the shepherd replies.
The math biologist ponders for a moment and then says: "I will give you the precise number of sheep in your herd without counting. If I'm right, don't you think that I deserve one of them as a reward?"
The shepherd nods.
The math biologist says: "387".
The shepherd is silent for a while and then says: "You're right. I hate to loose any of my sheep, but I promised: One of them is yours. Have your pick!"
The math biologist grabs one of the animals, puts it on his shoulders, and is about to march on, when the shepherd says: "Wait! I will tell you what your profession is, and if I'm right I'll get the animal back."
"That's fair enough."
"You must be a mathematical biologist."
The man is stunned. "You're right. But how could you know?"
"That's easy: You gave me the precise number of sheep without counting - and then you picked my dog..."

"Isn't statistics wonderful?"
"How so?"
"Well, according to statistics, there are 42 million alligator eggs laid every year. Of those, only about half get hatched. Of those that hatch, three fourths of them get eaten by predators in the first 36 days. And of the rest, only 5 percent get to be a year old for one reason or another. Isn't statistics wonderful?"
"What's so wonderful about all that?"
"If it weren't for statistics, we'd be up to our asses in alligators!"

Q: What is the fundamental principle of engineering mathematics?
A: Every function has a Taylor series which converges to the function and breaks off after the linear term.

"Wasn't yesterday your and your wife's first wedding anniversary? What is it like having being married to a mathematician for a whole year?"
"She just filed for divorce..."
"I don't believe it! Did you forget about your wedding day?"
"No. Actually, on my way back home from work, I stopped at a flower store and bought a bouquet of red roses for my wife. When I came home, I gave her the roses and said: `I love you.'"
"So, what happened?!"
"Well, she took the roses, slapped them around my face, kicked me in the groin, and threw me out of our appartment..."
"What a bitch!"
"No, no... it's all my fault... I should have said: `I love you and only you.'."

A pure and an applied mathematician are asked to calculate 2 * 2.
The applied mathematician's solution: We have

A physics professor has been conducting experiments and has worked out a set of equations which seem to explain his data. Nevertheless, he is unsure if his equations are really correct and therefore asks a colleague from the math department to check them.
A week later, the math professor calls him: "I'm sorry, but your equations are complete nonsense."
The physics professor is, of course, disappointed. Strangely, however, his incorrect equations turn out to be surprisingly accurate in predicting the results of further experiements. So, he asks the mathematician if he was sure about the equations being completely wrong.
"Well", the mathematician replies, "they are not actually complete nonsense. But the only case in which they are true is the trivial one where the field is Archimedean..."

"The number you have dialled is imaginary. Please, rotate your phone by 90 degrees and try again..."

Q: Do you already know the latest stats joke?
A: Probably...

A mathematician gives a talk intended for a general audience. The talk is announced in the local newspaper, but he expects few people to show up because nobody who is not a mathematician will be able to make any sense of the title: Convex sets and inequalities.
To his surprise, the auditorium is crammed when his talk begins. After he has finished, someone in the audience raises his hand.
"But you said nothing about the actual topic of your talk!"
"What topic to you mean?"
"Well, the one that was announced in the paper: Convicts, sex, and inequality."

George W. Bush visits Algeria. As part of his program, he delivers a speech to the Algerian people: "You know, I regret that I have to give this speech in English. I would very much prefer to talk to you in your own language. But unfortunately, I was never good at algebra..."

At the end of his course on mathematical methods in optimization, the professor sternly looks at his students and says: "There is one final piece of advice I'm going to give you now: Whatever you have learned in my course - never ever try to apply it to your personal lives!"
"Why?" the students ask.
"Well, some years ago, I observed my wife preparing breakfast, and I noticed that she wasted a lot of time walking back and forth in the kitchen. So, I went to work, optimized the whole procedure, and told my wife about it."
"And what happened?!"
"Before I applied my expert knowledge, my wife needed about half an hour to prepare breaksfast for the two of us. And now, it takes me less than fifteen minutes..."

A French mathematician's pick up line: "Voulez vous Cauchy avec moi?"

"My life is all arithmetic", the young businesswoman explains. "I try to add to my income, subtract from my weight, divide my time, and avoid multiplying..."

A graduate student of mathematics who used to come to the university on foot every day arrives one day on a fancy new bicycle.
"Where did you get the bike from?" his friends want to know.
"It's a `thank you' present", he explains, "from that freshman girl I've been tutoring. But the story is kind of weird..."
"Tell us!"
"Well", he starts, "yesterday she called me on the phone and told me that she had passed her math final and that she wanted to drop by to thank me in person. As usual, she arrived at my place riding her bicycle. But when I had let her in, she suddenly took all her clothes off, lay down on my bed, smiled at me, and said: `You can get from me whatever you desire!'"
One of his friends remarks: "You made a really smart choice when you took the bicycle."
"Yeah", another friend adds, "just imagine how silly you would have looked in a girl's clothes - and they wouldn't have fit you anyway!"

Q: What is normed, complete, and yellow?
A: A Bananach space...

A father who is very much concerned about his son's bad grades in math decides to register him at a catholic school. After his first term there, the son brings home his report card: He's getting "A"s in math.
The father is, of course, pleased, but wants to know: "Why are your math grades suddenly so good?"
"You know", the son explains, "when I walked into the classroom the first day, and I saw that guy on the wall nailed to a plus sign, I knew one thing: This place means business!"

At a conference, a mathematician proves a theorem.
Someone in the audience interrupts him: "That proof must be wrong - I have a counterexample to your theorem."
The speaker replies: "I don't care - I have another proof for it."

A mathematician has been invited to speak at a conference. His talk is announced as

The mother of already three is pregnant with her fourth child.
One evening, the eldest daughter says to her dad: "Do you know, daddy, what I've found out?"
"No."
"The new baby will be Chinese!"
"What?!"
"Yes. I've read in the paper that statistics shows that every fourth child born nowadays is Chinese..."

A math student and a computer science student are jogging together in a park when they hear a voice: "Please, help me!"
They stop and look. The voice belongs to a frog sitting in the grass.
"Please, help mel!" the frog repeats. "I'm not really a frog: I'm an enchanted, beautiful princess. Kiss me, and the spell will be broken - and I will be yours forever..."
The CS student picks up the frog and examines it carefully from all sides - making not even an attempt to kiss it.
"You don't have to marry me", the frog continues frantically, "if you're afraid of the commitment. I'll do whatever you wish me to do if you just kiss me..."
The frog's voice is silenced, when the CS student puts the animal into the right pocket of his pants.
"But why don't you kiss her?!" the math student asks.
"You know", the CS student replies, "I simply don't have time for a girlfriend - but a frog that talks makes a really cool pet..."

Psychologists subject an engineer, a physicist, and a mathematician - a topologist, by the way - to an experiment: Each of them is locked in a room for a day - hungry, with a can of food, but without an opener; all they have is pencil and paper.
At the end of the day, the psychologists open the engineer's room first. Pencil and paper are unused, but the walls of the room are covered with dents. The engineer is sitting on the floor and eating from the open can: He threw it against the walls until it cracked open.
The physicist is next. The paper is covered with formulas, there is one dent in the wall, and the physicist is eating, too: He calculated how exactly to throw the can against the wall, so that it would crack open.
When the psychologists open the mathematician's room, the paper is also full of formulas, the can is still closed, and the mathematician has disappeared. But there are strange noises coming from inside the can...
Someone gets an opener and opens the can. The mathematician crawls out. "Damn! I got a sign wrong..."

A physicist, a statistician, and a (pure) mathematician go to the races and place bets on horses.
The physicist's horse comes in last. "I don't understand it. I have determined each horse's strength through a series of careful measurements."
The statistician's horse does a little bit better, but still fails miserably. "How is this possible? I have statistically evaluated the results of all races for the past month."
They both look at the mathematician whose horse came in first. "How did you do it?"
"Well", he explains. "First, I assumed that all horses were identical and spherical..."

A physicist, a mathematician and a computer scientist discuss what is better: a wife or a girlfriend.
The physicist: "A girlfriend. You still have freedom to experiment."
The mathematician: "A wife. You have security."
The computer scientist: "Both. When I'm not with my wife, she thinks I'm with my girlfriend. With my girlfriend it's vice versa. And I can be with my computer without anyone disturbing me..."

Q: What is a topologist?
A: A person who cannot tell a doughnut from a coffee mug.

"What happened to your girlfriend, that really cute math student?"
"She no longer is my girlfriend. I caught her cheating on me."
"I don't believe that she cheated on you!"
"Well, a couple of nights ago I called her on the phone, and she told me that she was in bed wrestling with three unknowns..."

A group of mathematicians and a group of engineers are traveling together by train to attend a conference on mathematical methods in engineering. Each engineer has a ticket whereas only one of the mathematicians has one. Of course, the engineers laugh at the unworldly mathematicians and look forward to the moment the conductor shows up.
Suddenly one of the mathematicians shouts: "Conductor coming!"
All the mathematicians disappear into one washroom.
The conductor checks the ticket of each engineer and then knocks at the washroom door: "Your ticket, please."
The mathematicians stick the one ticket they have under the door, the conductor checks it and leaves. A few minutes later, when it is safe, the mathematicians come out of the washroom. The engineers are impressed.
When the conference has come to an end, the engineers decide that they are at least as smart as the mathematicians and also buy just one ticket for the whole group. This time the mathematicians have no ticket at all...
Again one of the mathematicians shouts: "Conductor coming!".
All the engineers rush off to one washroom. One of the mathematicians goes to that washroom, knocks at the door, and says: "Your ticket, please..."

In the old days of the cold war, when it was very hard for Westerners to visit the Soviet Union, a British mathematician travels to Moscow to speak in the seminar of a famous Russian professor.
He starts his talk writing a theorem on the board. When he wants to prove it, the professor interrupts him: "This theorem is clear!"
The speaker is, of course, annoyed, but manages to conceal it. He continues his talk with a second theorem, but, again, when he wants to start with the proof, he is interrupted by his host: "This theorem is also clear!"
With a stern face, he writes a third theorem on the board and asks: "Is this theorem clear, too?!"
His host nods.
The visitor grins and says: "This theorem - is false..."

Some engineers are trying to measure the height of a flag pole. They only have a measuring tape and are quite frustrated trying to keep the tape along the pole: It falls down all the time.
A mathematician comes along and asks what they are doing. They explain it to him.
"Well, that's easy..."
He pulls the pole out of the ground, lays it down, and measures it easily.
After he has left, one of the engineers says: "That's so typical of these mathematicians! What we need is the height - and he gives us the length!"

A mathematician has spent years trying to prove the Riemann hypothesis - without success. Finally, he decides to sell his soul to the devil in exchange for a proof. The devil promises to deliver a proof within four weeks.
Four weeks pass, but nothing happens. Half a year later, the devil shows up again - in a rather gloomy mood.
"I'm sorry", he says. "I couldn't prove the Riemann hypothesis either. But" - and his face lightens up - "I think I found a really interesting lemma..."

Q: How does a mathematician call his dog?
A: Cauchy - because it leaves a residue at every pole...

Two men are having a good time in a bar. Outside, there's a terrible thunderstorm. Finally, one of the men thinks that it's time to leave. Since he has drunk a lot, he decides to walk home.
"But aren't you afraid of being struck by lightning?" his friend asks.
"Not at all. Statistics shows that, in this part of the country, one person per year gets struck by lightning - and that one person died in the hospital three weeks ago."

After the phenomenal success of Viagra, Pfizer has come up with yet another pharmaceutical sensation: knowledge pills.
A student who is way behind in his English literature class, goes to the pharmacy, and asks the pharmacist if there are knowledge pills for English literature.
"Sure", the pharmacist replies.
The student buys one, swallows it, and hours later he knows everything there is to know about English literature. If it's that easy to acquire knowledge, he thinks, why waste hours wrecking your brains over boring textbooks? So, he gives up studying, and whenever an exam is near, he goes to the pharmacy and buys the right knowledge pill: biology, art history, world history - you name it.
When he has to take a math exam, he goes again to the pharmacy as asks for a knowledge pill for mathematics.
"Just wait a moment", the pharmacist says. He disappears in the back of his store and comes back with a pill of the size of a melon.
"But how am I supposed to swallow this?!" the student exclaims.
"Well, math has always been a little hard to swallow..."

In a class, a math professor claims that he can prove everything under the assumption that 1+1=1.
A student challenges him: "Then prove that you're the pope!"
He ponders for a moment and then replies: "I am one, and the pope is one. Therefore, the pope and I are one."

A mathematician, an engineer, and a computer scientist are vacationing together. They are riding in a car, enjoying the countryside, when suddenly the engine stops working.
The mathematician: "We came past a gas station a few minutes ago. Someone should go back and ask for help."
The engineer: "I should have a look at the engine. Perhaps, I can fix it."
The computer scientist: "Why don't we just open the doors, slam them shut, and see if everything works again?"

Let epsilon be less than zero...

Not really a joke, but rather a mathematician detection device: Tell it at a party, and those who laugh must be mathematicians.

Two math professors are sitting in a pub.
"Isn't it disgusting", the first one complains, "how little the general public knows about mathematics?"
"Well", his colleague replies, "you're perhaps a bit too pessimistic."
"I don't think so", the first one replies. "And anyhow, I have to go to the washroom now."
He goes off, and the other professor decides to use this opportunity to play a prank on his colleague. He makes a sign to the pretty, blonde waitress to come over.
"When my friend comes back, I'll wave you over to our table, and I'll ask you a question. I would like you to answer: x to the third over three. Can you do that?"
"Sure." The girl giggles and repeats several times: "x to the third over three, x to the third over three, x to the third over three..."
When the first professor comes back from the washroom, his colleague says: "I still think, you're way too pessismistic. I'm sure the waitress knows a lot more about mathematics than you imagine."
He makes her come over and asks her: "Can you tell us what the integral of x squared is?"
She replies: "x to the third over three."
The other professor's mouth drops wide open, and his colleage grins smugly when the waitress adds: "...plus C."

A mathematician, a physicist, and an engineer are asked to test the following hypothesis: All odd numbers greater than one are prime.
The mathematician: "Three is a prime, five is a prime, seven is a prime, but nine is not a prime. Therefore, the hypothesis is false."
The physicist: "Three is a prime, five is a prime, seven is a prime, nine is not a prime, eleven is a prime, and thirteen is a prime. Hence, five out of six experiments support the hypothesis. It must be true."
The engineer: "Three is a prime, five's a prime, seven's a prime, nine's a prime..."

In a dark, narrow alley, a function and a differential operator meet:
"Get out of my way - or I'll differentiate you till you're zero!"
"Try it - I'm e^x..."

Same alley, same function, but a different operator:
"Get out of my way - or I'll differentiate you till you're zero!"
"Try it - I'm e^x..."
"Too bad... I'm d/dy."

Back in the old days - when slide rules were still the most sophisticated computing equipement available to scientists and engineers...
Engineering students are taking a math final. Of course, slide rules are not allowed. And, of course, someone is cheating and has brought a slide rule to the exam. He is hiding it under his desk, but the student sitting to his left - who is stuck on a difficult calculation - has noticed it.
"Hey", he whispers. "Can you help me? What's three times six?"
His classmate reaches for his slide rule, and after a few seconds replies: "Nineteen."
"Are you sure?"
The other student reaches again for his slide rule, and after another few seconds replies: "You're right. It's closer to eighteen - eighteen point three, to be precise."

Two men are sitting in the basket of a balloon. For hours, they have been drifting through a thick layer of clouds, and they have lost orientation completely. Suddenly, the clouds part, and the two men see the top of a mountain with a man standing on it.
"Hey! Can you tell us where we are?!"
The man doesn't reply. The minutes pass as the balloon drifts past the mountain. When the balloon is about to be swallowed again by the clouds, the man on the mountain shouts: "You're in a balloon!"
"That must have been a mathematician."
"Why?"
"He thought long and thoroughly about what to say. What he eventually said was irrefutably correct. And it was of no use whatsoever..."