**Old mathematicians never die – they just lose their functions. **

**Why is 6 afraid of 7? – Because 789. **

**What did one maths book say to the other maths book?
– I have a lot of problems. **

**En ingeniør, en fysiker og en matematiker får til opgave at bygge en hønsegård. De får en bestem mængde hønsenet, og skal så bygge den størst mulige hønsegård.
Ingeniøren bygger straks en kvadratisk hønsegård, men fysikeren bygger en kuppel, for så er der jo plads til flere høns i gården.
Matematikeren griner lidt af de andres forsøg. Så tager han hønsenettet og begynder at rulle det rundt om ham selv. Fysikeren og ingeniøren ser undrende til, mens matematikeren efterhånden har pakket sig selv helt ind i hønsenet. ¨Hvad i alverden laver du¨, spørger de. Og matematikeren svarer: ¨Jeg definerer mig selv til at være udenfor hønsegården¨. **

**Two hydrogen atoms walk into a bar. One says,
“I’ve lost my electron.”
The other says, “Are you sure?”
The first replies, “Yes, I’m positive…” **

**Spørgsmål: ¨Vælg et tal mellem 0 og 10¨.
Matematikerens svar: ¨Pi¨. **

**What insect is good at maths? – An accountAnt **

**Man skal ikke kaste med geologiske fragmenter, når man selv bor i et transparent kompleks. **

**En fysiker, en biolog og en matematiker sidder på en bakke, nyder den smukke natur, og ser på et tomt skur. En mand kommer gående og går ind i skuret. Lidt efter kommer der to mænd ud af skuret.
Fysikeren mumler lidt utilfredst; ¨Målefejl¨.
Biologen mumler for sig selv; ¨Reproduktion¨.
Matematikeren sidder længe tavst og ser meget utilfreds ud. Da han har siddet der et godt stykke tid kommer der pludselig en mand gående forbi dem og går ind i huset.
¨PYHA¨, råber matematikeren, ¨Nu er skuret tomt igen!¨**

**Der findes 10 slags mennesker
– Dem der ser alting binært, og dem der ikke gør.**

**En gruppe fysikere og en gruppe matematikere skal med tog til en stor konference. Da de står på peronnen og skal afsted, har fysikerne en billet hver, men matematikerne har kun købt en billet tilsammen. Dette undrer fysikerne sig meget over. Under togturen sidder den ene matematiker hele tiden og kigger ned af gangen. Pludselig råber han ¨konduktør¨, og straks løber alle matematikerne ind på det ene af togvognens toiletter (De står godt klemt sammen). Konduktøren kan selvfølgelig godt se at toilettet er optaget, så han banker på døren og siger: ¨Må jeg se billetten?¨. Matematikerne stikker så deres eneste billet under døren, og konduktøren er tilfreds.
Dette synes fysikerne jo er genialt, så på vejen hjem køber de kun en billet. Men denne gang har matematikerne slet ikke købt nogle billetter. Dette undrer fysikerne. Nu sidder der så en fysiker og holder øje med gangen, og da han råber ¨Konduktør¨ spurter alle fysikerne ud på det ene toilet.
Straks de alle er indenfor døren går en matematiker han og banker på døren og siger; ¨Må jeg se billetten¨. Fysikerne stikker selvfølgelig deres billet ud under døren, hvorefter matematikerne snupper den og løber ud på det andet toilet.**

**En ingeniør, en fysiker og en matematiker er ude at køre i tog.
De kommer forbi em mark hvorpå der står to sorte får.
¨Se¨, siger ingeniøren, ¨Alle får i verden er sorte¨.
¨Nej, nej¨, siger fysikeren, ¨¨Mindst to får i verden er sorte¨.
¨Ï er begge to galt på den¨, siger matematikeren, ¨Der er mindst to får i verden, som er sorte på den ene halvdel¨.**

**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.**

**There was once a young man who, in his youth, professed a desire to become a great writer. When asked to define ‘great’ he said:
‘I want to write stuff that the whole world will read, stuff that people will react to on a truly emotional level, stuff that will make them scream, cry, wail, howl in pain, desperation, and anger!’
He now works for Microsoft, writing Excel error messages. **

**Asked if he believes in one God, a mathematician answered:
‘ Yes, up to isomorphism.’ **

**Hvis Excel (eller et andet microsoft program) var en bil:**

**It would crash two or three times per day for no apparent reason. The driver is often hurt, but the car itself receives no permanent damage. You’d just accept this fact, restart the car, and begin your trip again.****Occasionally, your car would fail to restart after a crash, and you’d have to reinstall the engine. For some strange reason, you’d just accept this too.****You would be forced to buy a new model every 18 months, and your old model would have no resale value. Each new model would be bigger that the previous one, require more gas, and would operate differently. Furthermore, parts from the old car would not be interchangeable with the new car.****You could call a special phone number when you had a problem. The phone would be staffed by people who know less about your car than you do.****There would be a special Macintosh model, powered by the sun. However, it would only run on 5 percent of the roads and require different driving skills.****You would have to spend additional money to buy the operating manuals.****The oil, engine, gas and alternator warning lights would be replaced by a single warning light: “This car has performed an illegal operation.”****Before engaging, the airbag system would display a message, “Are you sure?”****Every time you looked under the hood, an obnoxious cartoon character would appear and ask if you need help. No matter how many time you refused help, it would keep appearing.****A special feature would let you automatically record the route for a particular trip, so you could repeat the trip automatically later on. However, after repeating the trip you always end up at a different location.**

**Biologists think they are biochemists,
Biochemists think they are Physical Chemists,
Physical Chemists think they are Physicists,
Physicists think they are Gods,
And God thinks he is a Mathematician.**

**A mathematician, a physicist, an engineer went again to the races and laid their money down. Commiserating in the bar after the race, the engineer says, ‘I don’t understand why I lost all my money. I measured all the horses and calculated their strength and mechanical advantage and figured out how fast they could run…’
The physicist interrupted him: ‘…but you didn’t take individual variations into account. I did a statistical analysis of their previous performances and bet on the horses with the highest probability of winning…’
‘…so if you’re so hot why are you broke?” asked the engineer. But before the argument can grow, the mathematician takes out his pipe and they get a glimpse of his well-fattened wallet. Obviously here was a man who knows something about horses. They both demanded to know his secret.
‘Well,’ he says, ‘first I assumed all the horses were identical and spherical…’ **

**An engineer, a physicist and a mathematician are staying in a hotel.
The engineer wakes up and smells smoke. He goes out into the hallway and sees a fire, so he fills a trash can from his room with water and douses the fire. He goes back to bed.
Later, the physicist wakes up and smells smoke. He opens his door and sees a fire in the hallway. He walks down the hall to a fire hose and after calculating the flame velocity, distance, water pressure, trajectory, etc. extinguishes the fire with the minimum amount of water and energy needed.
Later, the mathematician wakes up and smells smoke. He goes to the hall, sees the fire and then the fire hose. He thinks for a moment and then exclaims, ‘Ah, a solution exists!’ and then goes back to bed. **

**A physicist and a mathematician are sitting in a faculty lounge. Suddenly, the coffee machine catches on fire. The physicist grabs a bucket and leap towards the sink, filled the bucket with water and puts out the fire. Second day, the same two sit in the same lounge. Again, the coffee machine catches on fire. This time, the mathematician stands up, got a bucket, hands the bucket to the physicist, thus reducing the problem to a previously solved one. **

**An chemist, a physicist, and a mathematician are stranded on an island when a can of food rools ashore. The chemist and the physicist comes up with many ingenious ways to open the can. Then suddenly the mathematician gets a bright idea: ‘Assume we have a can opener …’ **

**A Mathematician (M) and an Engineer (E) attend a lecture by a Physicist. The topic concerns Kulza-Klein theories involving physical processes that occur in spaces with dimensions of 9, 12 and even higher. The M is sitting, clearly enjoying the lecture, while the E is frowning and looking generally confused and puzzled. By the end the E has a terrible headache. At the end, the M comments about the wonderful lecture.
E: ‘How do you understand this stuff?’
M: ‘I just visualize the process’
E: ‘How can you POSSIBLY visualize something that occurs in 9-dimensional space?’
M: ‘Easy, first visualize it in N-dimensional space, then let N go to 9′ **

**A team of engineers were required to measure the height of a flag pole. They only had a measuring tape, and were getting quite frustrated trying to keep the tape along the pole. It kept falling down, etc. A mathematician comes along, finds out their problem, and proceeds to remove the pole from the ground and measure it easily. When he leaves, one engineer says to the other: ‘Just like a mathematician! We need to know the height, and he gives us the length!’ **

**A mathematician and a physicist agree to a psychological experiment. The (hungry) mathematician is put in a chair in a large empty room and his favorite meal, perfectly prepared, is placed at the other end of the room. The psychologist explains, ‘You are to remain in your chair. Every minute, I will move your chair to a position halfway between its current location and the meal.’ The mathematician looks at the psychologist in disgust. ‘What? I’m not going to go through this. You know I’ll never reach the food!’ And he gets up and storms out.
The psychologist ushers the physicist in. He explains the situation, and the physicist’s eyes light up and he starts drooling. The psychologist is a bit confused. ‘Don’t you realize that you’ll never reach the food?’ The physicist smiles and replies: ‘Of course! But I’ll get close enough for all practical purposes!’ **

**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 magical chemical 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.’ **

**What is the difference between a Psychotic, a Neurotic and a mathematician? A Psychotic believes that 2 2=5. A Neurotic knows that 2 2=4, but it kills him. A mathematician simply changes the base. **

**To mathematicians, solutions mean finding the answers. But to chemists, solutions are things that are still all mixed up. **

**Golden rule for math teachers: You must tell the truth, and nothing but the truth, but not the whole truth. **

**Teacher: Now suppose the number of sheep is x…
Student: Yes sir, but what happens if the number of sheep is not x? **

**Cat Theorem:
A cat has nine tails.
Proof:
No cat has eight tails. A cat has one tail more than no cat. Therefore, a cat has nine tails. **

**The shortest math joke: let epsilon be < 0. **

**Q: Why did the mathematician name his dog ‘Cauchy’?
A: Because he left a residue at every pole. **

**Q: What’s a polar bear?
A: A rectangular bear after a coordinate transform. **

**Q: Why didn’t Newton discover group theory?
A: Because he wasn’t Abel. **

**Life is complex. It has real and imaginary components. **

**To vektorer v og w,holdte en fest. Så kom en tredie vektor v w og spurgte om
den måtte være med. “Ja”, svarede v, “kom bare indenfor, det er en lukket
fest.” **

**The graduate with a physics degree asks, “Why does it work?”
The graduate with an engineering degree asks, “How does it work?”
The graduate with an accounting degree asks, “How much will it cost?”
The graduate with a liberal arts degree asks, “Do you want fries
with that?” **

**En af mine kammerater kom for nyligt og fortalte mig, at han havde hørt, at
man for grupper kan definere en homomorfi f, så f(1)=1. Jeg gik
hovedrystende min vej og tænkte “nej, det er for ringe.” **

**the integral of z dz
from one to the squareroot of three
multiplied by cosine
of three pi over nine
is the log of the squareroot of e**

**A mathematician is a device for turning coffee into theorems (P. Erdos) **

**I do not think — therefore I am not.
Example: One evening Rene Descartes went to relax at a local tavern. The tender approached and said, “Ah, good evening Monsieur Descartes! Shall I serve you the usual drink?”. Descartes replied, “I think not.”, and promptly vanished. **

**Math is like love; a simple idea, but it can get complicated. **

**The difference between an introvert and extrovert mathematicians is: An introvert mathematician looks at his shoes while talking to you. An extrovert mathematician looks at your shoes. **

**Asked if he believes in one God, a mathematician answered:
” Yes, up to isomorphism.” **

**Several scientists were all posed the following question: What is 2 * 2 ?
The engineer whips out his slide rule (so it´s old) and shuffles it back and forth, and finally announces 3.99.
The physicist consults his technical references, sets up the problem on his computer, and announces it lies between 3.98 and 4.02.
The mathematician cogitates for a while, then announces: I don´t know what the answer is, but I can tell you, an answer exists!.
Philosopher smiles: But what do you mean by 2 * 2 ?
Logician replies: Please define 2 * 2 more precisely.
The sociologist: I don´t know, but is was nice talking about it.
Behavioral Ecologist: A polygamous mating system.
Medical Student : 4 All others looking astonished : How did you know ?? Medical Student : I memorized it. **

**Several scientists were all posed the following question: What is pi ?
The engineer said: It is approximately 3 and 1/7
The physicist said: It is 3.14159
The mathematician thought a bit, and replied It is equal to pi.
(A nutritionist: “Pie is a healthy and delicious dessert!” )**

**A mathematician, scientist, and engineer are each asked: “Suppose we define a horse’s tail to be a leg. How many legs does a horse have?” The mathematician answers “5”; the scientist “1”; and the engineer says “But you can’t do that! **

**A mathematician, a physicist, and an engineer are all given identical rubber balls and told to find the volume. They are given anything they want to measure it, and have all the time they need. The mathematician pulls out a measuring tape and records the circumference. He then divides by two times pi to get the radius, cubes that, multiplies by pi again, and then multiplies by four-thirds and thereby calculates the volume. The physicist gets a bucket of water, places 1.00000 gallons of water in the bucket, drops in the ball, and measures the displacement to six significant figures. And the engineer? He writes down the serial number of the ball, and looks it up. **

**The physicist and the engineer are in a hot-air balloon. Soon, they find themselves lost in a canyon somewhere. They yell out for help: “Helllloooooo! Where are we?”
15 minutes later, they hear an echoing voice: “Helllloooooo! You’re in a hot-air balloon!!”
The physicist says, “That must have been a mathematician.”
The engineer asks, “Why do you say that?”
The physicist replied: “The answer was absolutely correct, and it was utterly useless.” **

**An engineer, a physicist and a mathematician find themselves in an anecdote, indeed an anecdote quite similar to many that you have no doubt already heard. After some observations and rough calculations the engineer realizes the situation and starts laughing. A few minutes later the physicist understands too and chuckles to himself happily as he now has enough experimental evidence to publish a paper.
This leaves the mathematician somewhat perplexed, as he had observed right away that he was the subject of an anecdote, and deduced quite rapidly the presence of humor from similar anecdotes, but considers this anecdote to be too trivial a corollary to be significant, let alone funny. **

**New York (CNN). At John F. Kennedy International Airport today, a high school mathematics teacher was arrested trying to board a flight while in possession of a compass, a protractor and a graphical calculator. According to law enforcement officials, he is believed to have ties to the Al-Gebra network. He will be charged with carrying weapons of math instruction. It was later discovered that he taught the students to solve their problem with the help of radicals!**

**A mathematician organizes a lottery in which the prize is an infinite amount of money. When the winning ticket is drawn, and the jubilant winner comes to claim his prize, the mathematician explains the mode of payment: “1 dollar now, 1/2 dollar next week, 1/3 dollar the week after that…” **

**A Mathematician was put in a room. The room contains a table and three metal spheres about the size of a softball. He was told to do whatever he wants with the balls and the table in one hour. After an hour, the balls are arranges in a triangle at the center of the table. The same test is given to a Physicist. After an hour, the balls are stacked one on top of the other in the center of the table. Finally, an Engineer was tested. After an hour, one of the balls is broken, one is missing, and he’s carrying the third out in his lunchbox. **

**When a statistician passes the airport security check, they discover a bomb in his bag. He explains. “Statistics shows that the probability of a bomb being on an airplane is 1/1000. However, the chance that there are two bombs at one plane is 1/1000000. So, I am much safer…”**

**A physicist has been conducting experiments and has worked out a set of equations which seem to explain his data. He asks a mathematician to check them. A week later, the mathematician calls “I’m sorry, but your equations are complete nonsense.” “But these equations accurately predict results of experiments. Are you sure they are completely wrong? “To be precise, they are not always a complete nonsense. But the only case in which they are true is the trivial one where the field is Archimedean…” **

**An engineer and a topologist were locked in the rooms for a day with a can of food but without an opener. At the end of the day, the engineer is sitting on the floor of his room and eating from the open can: He threw it against the walls until it cracked open. In the mathematician’s room, the can is still closed but the mathematician has disappeared. There are strange noises coming from inside the can… When it is opened and the mathematician crawls out. “Damn! I got a sign wrong…” **

**The Evolution of Math Teaching:
1960s: A peasant sells a bag of potatoes for $10. His costs amount to 4/5 of his selling price. What is his profit?
1970s: A farmer sells a bag of potatoes for $10. His costs amount to 4/5 of his selling price, that is, $8. What is his profit?
1970s (new math): A farmer exchanges a set P of potatoes with set M of money. The cardinality of the set M is equal to 10, and each element of M is worth $1. Draw ten big dots representing the elements of M. The set C of production costs is composed of two big dots less than the set M. Represent C as a subset of M and give the answer to the question: What is the cardinality of the set of profits?
1980s: A farmer sells a bag of potatoes for $10. His production costs are $8, and his profit is $2. Underline the word potatoes and discuss with your classmates.
1990s: A farmer sells a bag of potatoes for $10. His or her production costs are 0.80 of his or her revenue. On your calculator, graph revenue vs. costs. Run the POTATO program to determine the profit. Discuss the result with students in your group. Write a brief essay that analyzes this example in the real world of economics.
**

**A mathematician, native Texan, once was asked in his class: “What is mathematics good for?” He replied: “This question makes me sick. Like when you show somebody the Grand Canyon for the first time, and he asks you `What’s is good for?’ What would you do? Why, you would kick the guy off the cliff”. **

**A somewhat advanced society has figured how to package basic knowledge in pill form.
A student, needing some learning, goes to the pharmacy and asks what kind of knowledge pills are available. The pharmacist says “Here’s a pill for English literature.” The student takes the pill and swallows it and has new knowledge about English literature!
“What else do you have?” asks the student.
“Well, I have pills for art history, biology, and world history,” replies the pharmacist.
The student asks for these, and swallows them and has new knowledge about those subjects.
Then the student asks, “Do you have a pill for math?”
The pharmacist says “Wait just a moment”, and goes back into the storeroom and brings back a whopper of a pill and plunks it on the counter.
“I have to take that huge pill for math?” inquires the student.
The pharmacist replied “Well, you know math always was a little hard to swallow.” **

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

**Mathematician U. was a great friend of his five-year old grandson. They discussed everything including math and U. was very proud of the boys math talents. The child went to kindergarten; In two weeks the he ask U.to help with the difficult math problem: “There are four airplanes flying, then two more airplanes join them. How many airplanes are flying now? U. was very disappointed by the simplicity of the problem. “What confuses you?” he asked. The child says: ” I know, of course, that 4 2 =6, but I cannot figure out what the airplanes have do with this!” **

**“This is a one line proof…if we start sufficiently far to the left.”**

**“The problems for the exam will be similar to the discussed in the class. Of course, the numbers will be different. But not all of them. Pi will still be 3.14159… ” **