A newlywed husband is discouraged by his wife's obsession with mathematics. Afraid of being second fiddle to her profession, he finally confronts her: "Do you love math more than me?" "Of course not, dear  I love you much more!"Happy, although sceptical, he challenges her: "Well, then prove it!" Pondering a bit, she responds: "Ok... Let epsilon be greater than zero..." 
"A molecular biologist with a PhD at University of Birmingham, in the UK, quits his lab position to become a plumber, since a plumber apparently earns twice what he currently makes (~US$42K)." True story. The following is a joke. One professor of mathematics noticed that his kitchen sink at his home broke down. He called a plumber. The plumber came on the next day, sealed a few screws and everything was working as before. The professor was delighted. However, when the plumber gave him the bill a minute later, he was shocked. "This is one third of my monthly salary!" he yelled. Well, he paid and then the plumber said to him: "I understand your position as a professor. Why don't you come to our company and apply for a plumber position? You will earn three times as much as a professor. But remember, when you apply tell them that you completed only the seventh grade. They don't like educated people." So it happened. The professor got a plumber job and his life significantly improved. He just had to seal a screw or two occasionally, and his salary went up significantly. One day, the board of the plumbing company decided that every plumber has to go to evening classes to complete the eighth grade. So, our professor had to go there too. It just happened that the first class was math. The evening teacher, to check students' knowledge, asked for a formula for the area of the circle. The person who was asked was the professor. He jumped to the board, and then he realized that he forgot the formula. He started to reason it and soon filled the board with integrals, differentials and other advanced formulas to conclude the result that he had forgotten. As a result he got "negative pi times r squared." He didn't like the negative, so he started all over again. He got the negative sign again. No matter how many times he tried, he always got a negative. He was frustrated. He looked a bit scared at the class and saw all the plumbers whisper: "Switch the limits of the integral!!"

Do Roman paramedics refer to IV's as "4's"? There are 3 kinds of people: those who can count and those who can't. Lottery: a tax on people who are bad at math If it's zero degrees outside today and it's supposed to be twice as cold tomorrow, how cold is it going to be? 
A mathematician went insane and believed that he was the differentiation operator. His friends had him placed in a mental hospital until he got better. All day he would go around frightening the other patients by staring at them and saying "I differentiate you!" One day he met a new patient; and true to form he stared at him and said "I differentiate you!", but for once, his victim's expression didn't change. Surprised, the mathematician marshalled his energies, stared fiercely at the new patient and said loudly "I differentiate you!", but still the other man had no reaction. Finally, in frustration, the mathematician screamed out "I DIFFERENTIATE YOU!" The new patient calmly looked up and said, "You can differentiate me all you like: I'm e to the x." 