Each semester, I offer students a last chance for extra credit by writing their favorite joke or riddle on their crib sheet, with extra credit assigned based purely on how funny I think it is. Here are some of the better ones.

## Mathy contributions

Q: What did the employed Math Ph.D. say to the unemployed Math Ph.D?

A: “Paper or plastic?”

Q: What can you always count on when things go wrong?

A: Your fingers.

Q: Why do mathematicians always take home part of their Chinese dinner for leftovers?

A: They know the Chinese Remainder Theorem.

Q: How many classic geometers does it take to screw in a lightbulb.

A: None. It’s known to be impossible with straightedge and compass.

“A mathematician is a blind man in a dark room looking for a black cat which isn’t there.”

— Charles Darwin

“As far as the laws of mathematics refer to reality, they are not certain; and as far as they are certain, they do not refer to reality.”

— Albert Einstein

“The trigonometric functions are like a group of Appalachian hillbillies. They’re all related to each other.”

— Travis Kowalski

A math professor is someone who talks in someone else’s sleep.

An engineer thinks that his equations are an approximation to reality. A physicist thinks reality is an approximation to his equations. A mathematician doesn’t care.

Old mathematicians never die. They just lose some of their functions.

Old statisticians never die. They’re just broken down by age and sex.

Two mathematicians walk into a bar, but the engineer ducks.

Chuck Norris can divide by zero.

Chuck Norris can count to infinity. On one hand.

Chuck Norris can watch *60 Minutes* in twenty.

In high school, a proof is a sequence of justified conclusions used to assert a geometric truth. In college, a proof is one-half of a percent of alcohol.

Heisenberg gets pulled over for speeding. “Sir, do you know how fast you were going,” asks the cop. “No,” says Heisenberg, “but I know where I am.”

There once was a number named *Pi*

Who sometimes liked to get high.

All he did everyday

Was toke up and play

With his imaginary friend named *i*.

Integrate *v* squared *dv*

From 1 to the cube root of 3

Times the cosine

Of thrice pi over nine

To get the log of cube root of *e*:

Equations of dubious truth:

Math pick-up lines:

- Hey baby, can I be your derivative? Because I want to tangent to your curves.
- Hey baby, can I be your integral? Because I want to be the area under your curves.
- Hey baby, did you just divide by zero? Because you’ve got one fine asymptote.
- Hey baby, do you wanna be my function? Because I’ve got something I want to plug into you.
- Hey baby, can I be your problem set? Because then I’d be really hard, and you’d be doing me on your desk.

Several people are asked to prove that all odd integers greater than 2 are prime.

- Tenured mathematician: 3 is prime, 5 is prime, 7 is prime, 9 is
*not*prime. Ha! A counterexample. - Untenured mathematician: 3 is prime, 5 is prime, 7 is prime… so by induction, all subsequent odd integers are prime.
- Statistician: Let’s verify this with several randomly selected odd numbers, say, 23, 47, and 83.
- Computer scientist: 3 is prime, 5 is prime, 7 is prime, segmentation fault?
- Computer programmer: 3 is prime, 3 is prime, 3 is prime, 3 is prime…
- Physicist: 3 is prime, 5 is prime, 7 is prime, 9 is an experimental error, 11 is prime…
- Mechanical engineer: 3 is prime, 5 is prime, 7 is prime, 9 is approximately prime, 1 is prime…
- Civil engineer: 3 is prime, 5 is prime, 7 is prime, 9 is prime…
- Biologist: 3 is prime, 5 is prime, 7 is prime, 9 is… still awaiting results…
- Psychologist: 3 is prime, 5 is prime, 7 is prime, 9 is prime but suppresses it, 11 is prime…
- Economist: 2 is prime, 4 is prime, 6 is prime…
- Politician: Shouldn’t the goal really be to create a greater society where
*all*numbers are prime? - Sarah Palin: What’s a prime?

Several people are asked to define what *pi* is:

- Tenured mathematician: The ratio of a circle’s circumference to its diameter.
- Untenured mathematician: Approximately 3.1415927.
- Physicist: 3.14, plus or minus .005.
- Engineer: 3.
- College student: Yummy.

Top ten reasons for not turning in your math homework:

- I’ve included a reference to the solutions manual, reducing this assignment to one previously solved.
- I couldn’t decide whether
*i*is the square root of -1 or*i*am the square root of -1. - I accidentally divided by 0 and my paper burst into flames.
- I put it inside a Klein bottle last night, but couldn’t find it this morning.
- I could only get arbitrarily close to my textbook.
- I had too much
*pi*and got sick. - I was watching the World Series and got caught up trying to determine if it converged.
- I locked it in a trunk, but a four-dimensional dog got in and ate it.
- I took time out to have a snack: a donut and a cup of coffee. I spent the rest of the night trying to figure out which one to drink.
- I have a nice proof, but there wasn’t enough room to in the margin to contain it.

Little Jimmy comes home in a huff. “My teacher is *a liar!*” he cries. “Why?” asks his mother, concerned. “Yesterday he told us that 5 is 4 plus 1,” he explains, “but today she kept telling us that 5 is 3 plus 2!”

Teacher: What’s 3 and 3?

Pupil: 6.

Teacher: That’s good!

Pupil: Good? That’s *perfect*!

A blonde is trying to understand limits in her calculus class. Her teacher goes through various examples and lessons, eventually showing that

To check she’s really understood, the teacher then gives the blonde a different exercise. The blonde thinks for a moment, and then writes the following:

Two mathematicians walk into in a bar. The first one says to the second that the average person knows very little about basic mathematics. The second one disagrees, and claims that most people can cope with a reasonable amount of math. The first mathematician goes off to the washroom, and in his absence the second calls over the waitress. He tells her that in a few minutes, after his friend has returned, he will call her over and ask her a question. All she has to do is answer “one third *x* cubed.” She repeats: “one thir dex cue?” He repeats “one third x cubed. ” “One thir dex cuebd? ” “Yes, that’s right “, he says. So she agrees, and goes off mumbling to herself, “one thir dex cuebd… one thir dex cuebd… one thir dex cuebd… ” The first guy returns and the second proposes a bet to prove his point, that most people do know something about basic math. He says he will ask the blonde waitress an integral, and the first laughingly agrees. The second man calls over the waitress and asks “What is the integral of *x* squared?” The waitress says “one third *x* cubed” and while walking away, turns back and adds with a wink “…plus a constant.”

An infinite number of mathematicians walk into a bar. The first orders a beer. The second orders half a beer. The third orders a quarter of a beer. Before the next one can order, the bartender says, “You’re all assholes,” and pours two beers.

An engineer and a mathematician are pumping gas into their respective vehicles at the local gas station: the engineer into his rebuilt Corvette, and the mathematician into his beat-up old moped. The mathematician slides his glasses up his nose, adjusts his pocket protector and his suspenders, and lets out a low whistle. “That’s a nice ride,” he comments. “Sure is,” replies the engineer as he pats his car. Feeling a bit cocky, he adds “You wanna race, Rain Man?” “Sure,” says the mathematician, but let’s make it interesting: I’ll wager my moped for your Vette.” The moped isn’t much to look at, but the engineer can already see ways to soup it up, and since he can easily win it, readily agrees. The two men shake hands to seal the deal. The engineer hops into his car and quickly revs it up to second gear, leaving the mathematician in his dust. “What a waste of time,” he thinks, when suddenly, **ZZZOOOOOOMMMMMM!** The mathematician zips by on his moped with a smile. “Whoa!” exclaims the engineer, who slams the Vette into third gear and speeds up, racing past the moped until its nothing but a dot in the rear-view mirror. But then, suddenly, **ZZZOOOOOOMMMMMM!** To the engineer’s surprise the moped flies by again! The engineer decides to go all out, shifts into sixth gear and puts the pedal to the floor. The Vette screams by the moped, and leaves it beyond the horizon in a cloud of exhaust fumes and churned asphalt. But moment’s later, **ZZZOOOOOOMMMMMM!** and the mathematician and his moped fly by again, practically blowing the Vette’s doors off. The Vette starts to sputter, pushed past its limits, so the engineer reluctantly slows it down and pulls up to the moped, parked a ways ahead of him. The engineer is understandably disappointed to lose his Vette, but he’s also thrilled by the chance to understand the secret of the mathematician’s moped. He hands his keys to the mathematician and looks over the beat up moped in awe. “I have to know,” he barely breathes, “what kind of engine do you have in there?” “I dunno,” shrugs the mathematician as he gets in the ‘Vette. As he pulls away, he adds: “I just stuck my suspenders in your car’s doors and held on.”

A nerdy mathematician walks into a jewelry store one Friday evening with an unbelievably beautiful young gal on his arm. “I’m looking for a special ring for my special girl,” he tells the jeweler. The jeweler looks through his stock and brings out a $1000 gold ring. The mathematician shakes his head: “No, she’s more special than that.” The jeweler looks through his special stock and brings out a $5000 diamond ring. The mathematician shakes his head: “No, she’s still more special than that.” So the jeweler goes to his office and returns with a stunning diamond encrusted ring worth $40,000. The young lady’s eyes sparkle and her whole body trembles with excitement. The mathematician smiles and says “We’ll take it.” The jeweler asks how payment shall be made, to which the mathematician replies, “By check. I know you need to make sure my check is good, so I’ll write it now. You can call the bank on Monday to verify the funds, after which I’ll pick the ring up on Monday afternoon.” He writes his check, and walks out the store with the lady curled up even closer to him. On Monday morning, the mathematician receives a call from the jeweler. “I’m sorry, sir, but your bank says you have no money in that checking account.” “Yeah,” admits the mathematician, “I know. But let me tell you about my weekend!”

A mathematician, an engineer, and a chemist were walking down the road when they saw a pile of cans of beer. Unfortunately, they were the old-fashioned cans that do not have the tab at the top. One of them proposed that they split up and find can openers. The chemist went to his lab and concocted a chemical solution that dissolves the can top in an instant and evaporates the next instant so that the beer inside is not affected. The engineer went to his workshop and created a new HyperOpener that can open 25 cans per second.They went back to the pile with their inventions and found the mathematician finishing the last can of beer. “How did you manage that?” they asked in astonishment. The mathematician answered, “Oh, well, I assumed they were open and went from there.”

Five surgeons are taking a coffee break, discussing which kind of professional is the best to operate on. The first surgeon says: “Accountants are the best. When you open them up, everything inside is numbered.” The second surgeon says: “Librarians are the best. Everything inside them is in alphabetical order.” The third surgeon responds: “Electricians are the best. Everything inside *them* is color coded.” The fourth surgeon intercedes: “Lawyers are best. They’re heartless, spineless, gutless and their heads and asses are interchangeable.” The fifth surgeon thinks about this, then finally decides: “I think engineers are best. They always understand when you have a few pieces left over at the end.”

A doctor, a lawyer and a mathematician were discussing the relative merits of having a wife or a mistress. “For sure a mistress is better,” says the lawyer. “If you have a wife and want a divorce, it causes all sorts of legal problems.” “No, no, it’s better to have a wife,” says the doctor, “because the sense of security lowers your stress and is good for your health. “No, no, you’re both wrong,” replies the mathematician. “It’s best to have both so that when the wife thinks you’re with the mistress and the mistress thinks you’re with your wife, you can slip away and do some mathematics.”

A statistician is passing through airport security when they discover a bomb in his bag. After being detained and questioned about the bomb, the statistician admits that it’s his, but adds that he only brought it to “ensure everyone on board had a really safe flight.” Dumbfounded, the Head TSA agent demands “How the hell is bring an bomb onto the plane going to make the flight any safer?” “Simple,” the statistician explains. “Data shows that the probability of a bomb being on board an airplane is 10^{-3}, or one one-thousandth. Therefore, the probability of *two* bombs on the same plane is therefore 10^{-6}, or one one-millionth, so…”

A statistician had a habit of rapidly speeding up as he approached an intersection, whizzing right through it at breakneck speed, then rapidly decelerating to the speed limit once he had gotten past it. When the day came for him to be the driver of the university carpool, his passengers were quickly (and understandably) unsettled by his driving style. “Dude!” cried his mathematician colleague, his fingers white from clutching the seat) finally asked why he we, “why are you driving through all these intersections so fast?” “Basic statistics,” the driver replies. “A person is far more likely to have an accident at an intersection, so I just make sure that I spend less time there.”

Three statisticians went deer hunting. They spied a deer in the woods. The first statistician shot, and missed the deer by being a foot too far to the left. The second statistician shot, and missed the deer by being a foot too far to the right. The third cried, “We hit it!”

Two engineers are out hunting in the woods when one of them collapses. He’s not breathing, so in a panic the other dials 9-1-1 on his cell phone. He cries “My friend is dead! What can I do?” The operator replies, “Calm down “¦ I can help! First, let’s make sure he’s dead.” There is a silence, followed by sound of a rifle blast. Back on the phone, the engineer says “Okay, now what?”

A mathematician and a physicist were walking along during their lunch break when at a two-day convention when they realized they are going to be late for the afternoon session. “We’re going to be late,” says the physicist. So the two begin to scramble back to their seats. However, no sooner do they start then they spy the engineering building on fire. Immediately, the physicist springs into action. He finds a nearby length of hose, jerry-rigs it to a nearby fire hydrant, and quickly puts the fire out. He then rushes into the building to make sure everyone is okay (they are). He then grabs the mathematician’s arm and rushes back to their seats. Amazingly, they make it on time. The next day, the pair are again out walking about on their lunch break when they realize they are going to be late for the afternoon session. Immediately the mathematician springs into action. He sets the nearby engineering building on fire, thus reducing the problem to one previously solved.

Mrs. Jones, the math teacher, asks little Jimmy, “If there were 5 birds sitting on a phone line and you shot and killed one, how many would be left?” Jimmy answers “None.” Mrs. Jones says, “No. If there were 5 birds and you shot one, then 5 take away 1 leaves 4 birds left.” Jimmy replies, “No. If I shot and killed one of the birds, the others would fly away, ’cause they’d see how good a shot I was.” Mrs. Jones smiles and says “Good point. I like the way you think.” Jimmy looks up and says “Now I have a question for you. Three woman are eating ice cream, and one is licking it, one is sucking it, and one is biting it. Which one is married?” Mrs. Jones thinks for a bit and says, “Ummmmm… the one biting it?” Jimmy smiles and says, “No, the one with the wedding band on. But I like the way you think.”

Two atoms walk out of a bar. “Oh dear, I’ve left my electrons back in the bar.” “Are you sure?” “I’m positive.”

All the functions go to a party. After some drinks and music, the party is really going, with one exception: *e ^{x}* is standing awkwardly by himself in a dark corner. After a while sin(

*x*) notices this, and so he goes over to talk to his nonalgebraic buddy. “Hey

*e*,” says sin(

^{x}*x*), “why don’t you come out here and mingle.” “Mingle?” asks

*e*, suprised. “Yeah, mingle!” says sin(

^{x}*x*). “You know, get out there and integrate yourself!” To which

*e*sighs heavily and asks, “What’s the point?”

^{x}Here’s a comic from (x,why?):

A popular proof:

(It’s worth noting that I disproved this back in 2003.)

From the U.S. Census Bureaus’s Employment website:

Other good images:

## Other good ones

At first I hated the beard that was growing on my face, but now it’s really growing on me.

Q: Why does Santa enjoy gardening so much?

A: He likes to HO HO HO!

There is this guy who walks into a bar and notices a tiny man, only a foot tall playing fantastic jazz tunes on a miniature grand piano. He asks what it is all about and the barman say “Buy a drink and I’ll tell you.” So he buys a drink and asks again. The barman pulls out a beat-up old lamp. “It got it from this,” he says. The guy is confused, and says “Whadya mean?” The barman says “Buy another drink and I’ll tell you.” Intrigued, the guy buys another drink and asks again. “It’s a magic lamp,” says the barman. “If you rub it, a genie will grant you one wish.” “Incredible!” says the patron, who then adds “Why on Earth would you wish for a tiny jazz player?” The barman says, “Buy another drink and I’ll tell you.” So the guy buys his third round and asks again. To his surprise, the barman hands him the lamp and says, “Make a wish.” Wide-eyed and in disbeliefe, the patron rubs the lamp and — **POOF!** — a wrinkled old genie pops out of it. “I will grant you one wish,” says the wizened old creature. The guy thinks about it and then announces “I wish for a million bucks.” “It is done,” says the genie, who disappears in an explosion of light and smoke. When the smoke clears, the patron is astonished to find that he is surrounded not by mounds of cash, but by an immense number of quacking ducks. “Hey!” cries the patron, “I wished for a million *bucks*, not a million *ducks*.” “Don’t blame me, man,” says the barman. “You think I wished for a twelve-inch pianist?”

On Wednesday morning, a pair of brunettes are doing jumping jacks in the middle of an interstate, chanting “*69! 69! 69!*” over and over again as cars fly around them on either side. A blonde drives up to get some gas, sees the brunettes jumping, and is immediately intrigued. “*69! 69! 69!*” shout the brunettes as cars whisk by on either side. She pumps her gas, and goes inside to get some munchies for her trip. As she leaves, she still finds the brunettes jumping away. “*69! 69! 69!*” Her curiosity gets the best of her, so she puts her purchases in her car and runs out into the interstate. She stands in front of the brunettes, and begins doing jumping jacks, joining in with the chant. “*69! 69! 69!*” she chants as the cars whisk on by. Suddenly a truck comes down the road, and the two brunettes quickly jump onto the median while the blonde continues jumping and chanting away. The truck hits her with a **WHAM!**… On Thursday morning, a pair of brunettes are doing jumping jacks in the middle of an interstate, chanting “*70! 70! 70!*” over and over again as cars fly around them…

Little Susie was not the best student in Catholic School. Usually she slept through the class. One day while Mother Superior was teaching a lesson on the Creation, she called on Susie while she was sleeping. “Tell me Susie, who created the universe?” When Susie didn’t stir, little Johnny who was her friend sitting behind her, took his pencil and jabbed her in the rear. “God Almighty!” shouted Susie. “Very good,” said Mother Superior, and continued teaching her class. Little Susie quickly fell back asleep. A little later the nun asked Susie, “Who is our Lord and Savior?” But Susie didn’t stir from her slumber, so Johnny came to her rescue and once again stuck her in the butt. “Jesus Christ!” shouted Susie. “Very good,” and Mother Superior, and Susie fell back asleep. Near the end of class, the nun called upon Susie once again: “What did Eve say to Adam after she had borne her twenty-third child?” Johnny once again poked Susie’s rear with his pencil, but this time she stood up, grabbed him by the scruff of his neck, and snarled “If you stick that damn thing in me one more time, I’ll break it in half!”

While driving to a mission site, a bus full of nuns crashes. Four of the nuns die and present themselves to St. Peter. “Well good sisters,” the archangel says, “before you can enter the gates, you must be purified. Because of your good works you will be granted a final confession with which to admit your deepest darkest sins. You will confess your sin then wash the afflicted flesh with holy water from this font.” The first nun steps up. “Merciful St. Peter, in my youth I was sorely tempted with a young monk. I saw watched him pleasure himself”. She approaches the water and scoops some into her eyes. Thus purified, she passes through the gates. The second nun steps up. “Merciful St. Peter, in my youth I was sorely tempted as well. But I could not resist and I helped him reach his climax with my hands”. She approaches the water and washes her hands in it. The third nun steps up. “Merciful St. Pe-” she begins, but she is quickly cut off by the fourth nun, who cries out “Hold on a minute! I’ll be damned if I’m going to gargle with that after she puts her ass in there!”

A young boy went up to his father and asked him, “Dad, what is the difference between potentially and realistically?” The father thought for a moment, then answered, “Go ask your sister and your mother if they would sleep with Brad Pitt for a million dollars. Then come back and tell me what you learn from that.” So the boy asks his sister, who quickly answers with “Oh my God! I LOVE Brad Pitt! I would sleep with him in a heartbeat, are you nuts?” Then the boy went to his mother and asked her. She thinks about it for a long while before answering: “Yes, I would. We could really use that money to fix up the house and send you kids to a great University!” The boy ponders the answers for a few days, then goes back to his dad. “So son,” asks the father, “did you find out the difference between potentially and realistically?” “I think so,” says the boy. “Potentially, you and I are sitting on two million dollars, but realistically we’re just living with two whores.”

## And the winner is…

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

A: They thought they had a good dot product.