# Math jokes

The jokes below try to grab certain ways of mathematical thinking. No offense is intended, these differences in mentality are probably necessary for people in different professions to do their job properly.

Way of thinking

Pour out the water
How many legs does a sheep have?
What color are the sheep in Scotland?
The volume of a little red ball
Every girl is blonde
How do you define a mathematician?
Accuracy

Social position

The student, the assistant and the professor
Mathematics and Computer Science
The King’s Astronomer

## Way of thinking

### Pour out the water

How does a mathematician or a physicist prepare tea?
Both of them pour water into the pot, light the flame, boil the water, infuse the leaves.
What is the difference in the solution, if the pot is already filled with water?
The physicist lights the flame, boils the water, infuses the leaves.
The mathematician pours the water out, thereby reducing the problem to the previous, already solved one.

### How many legs does a sheep have?

Two in front, two in the back, two on the left side, two on the right. That is eight, but we counted each leg twice, so the result is four.

### What color are the sheep in Scotland?

A mathematician, a physicist and an engineer travel on a train in Scotland. They catch a glimpse of a sheep.

– Sheep in Scotland are black, it seems – ventures the engineer.
– You can be sure only that there is a black sheep in Scotland – answers the physicist.
– No, we know only that there is a sheep in Scotland with at least one black side – corrects the mathematician.

### The volume of a little red ball

A mathematician, a physicist and an engineer are asked to measure the volume of a little red ball.

The mathematician measures the diameter and calculates the volume.
The physicist drops the ball into a tank full of water, and measures how much water poured out.
The engineer looks up the volume in the Catalog of Little Red Balls.

### Every girl is blonde

Proof. It is sufficient to show that in every set of girls, any two members have the same hair color. Indeed, apply this to the set of all girls. Since there exists a blonde girl, every girl is blonde.

We prove the italicized statement by induction on the size of the set. If the size is one, the statement is clearly true. Suppose that the statement holds for every n element set of girls, and consider an n+1 element set: S={Kate, Julie, Ann, Elisabeth,…}. If Kate is dropped from S, then an n element set remains, and by the induction assumption, every girl in this subset has the same hair color, say X. Similarly, if Julie is dropped from S, then in this subset the hair color is uniform. But Ann’s hair is of color X, and so the same holds for Kate. Therefore the hair color is uniformly X in S, too.

### How do you define a mathematician?

A person is a mathematician, if he is willing to think for hours (and builds up a beautiful theory in the process) in order to spare a few minutes of ugly calculations.

### Accuracy

A plane flies over San Francisco in dense fog when the navigation equipment breaks down. The pilot opens the window and shouts:
Where am I?
In the air!
This information was sufficient to find the exact position, and the plane landed safely. How is this possible?

Solution: The response was completely accurate and completely useless, so it came from a mathematician. Therefore the plane was above Berkeley.

## Social position

### The student, the assistant and the professor

The student has to know everything.
The assistant has to know where the appropriate book is.
The professor has to know where the assistant is.

### Mathematics and Computer Science

What is the difference between two persons, doing research in the same area of combinatorics, if one works at a Math Department, and the other one at a Computer Science Department?

Answer: \$50000 per year (in wages).

### The King’s Astronomer

Who is this ragged man in my Court?
He is the Royal Astronomer.
What is the job of my Astronomer?
He prepares the maps for Your Majesty’s fleet.
And how can such an important man be so shabby?