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# All odd numbers are prime

#### tomhudson (43916) writes | more than 3 years ago

6

Lots of good examples, but this one is worth repeating

http://rationalwiki.org/wiki/Fun:Proof_that_all_odd_numbers_are_prime

Lots of good examples, but this one is worth repeating

* A liberal professor at a famous university lectured his class on what numbers were and were not prime. He started out by saying that the odd numbers 3, 5, and 7 were prime, but went on to say that 9 was not. A certain student, disapproving of simply being told by an "expert" what was or was not prime, raised his hand and asked a question.

"You say 9 is not prime, correct?"

"Correct," replied the liberal professor, who did not like being questioned by his students who obviously were nowhere near as smart as he was.

"But 9 is the sum of 7 and 2, is it not?"

"It is" replied the professor.

The student continued "But 7 and 2 are both prime, so how can anything which is the result of adding two similar things together have traits different from those it is the result of without adding new information?"

The professor's draw dropped at this, and he fled the classroom without a word. The remaining students cheered the logic of the brave student, and his willingness to stand up to liberal indoctrination.

The name of that student: Albert Einstein.

Some other good ones:

• English Major: 2 is prime, 3 is prime, 4 is prime...
• Physicist: 3 is prime, 5 is prime, 7 is prime, 9 is experimental error, 11 is prime, 13 is prime, 15 is experimental error, 17 is prime, 19 is prime. The empirical evidence is overwhelming.
• Keynesian Economist: Any quantity can be made prime by introducing more units of fiduciary media
• Meteorologist: 3 is clearly prime. If you add one, it becomes non-prime. If you add one again, it goes back to being prime. We predict that 7 and 9 will be prime.

Now go read the rest :-)

-- Barbie

cancel ×

#### plover (150551) | more than 3 years ago | (#34648910)

• MBA: Tom Peters told me all odd numbers are prime, therefore that will be the corporate direction for prime numbers.
• Architect: 3 is prime, 5 is prime, 7 is prime, the engineers will figure out how to make 9 prime, 11 is prime, ...
• Accountant: 3 is prime, 5 is prime, 7 is prime; uh, did you really need 9 to be prime? Because I could shift 2 more into this account and you'll have 11 which is prime, ...

Those are all I could think of off the top of my head.

#### tomhudson (43916) | more than 3 years ago | (#34656696)

Nice. Why not add them to the wiki article?

Done.

### Odd and Even numbers (1)

#### Stargoat (658863) | more than 3 years ago | (#34654562)

In a similar vein:

An even and an even are an even.
An odd and an even are an odd.
An odd and an odd are an even.

Conclusion: There are more even numbers than odd.

### Re:Odd and Even numbers (1)

#### tomhudson (43916) | more than 3 years ago | (#34656728)

In a similar vein:

An even and an even are an even. An odd and an even are an odd. An odd and an odd are an even.

Conclusion: There are more even numbers than odd.

Of course, since zero is even (evenly divisible by 2 with no remainder), and for every other positive number, there's an equivalent, but negative, number.

However, 0 + an even are still an even, so you could argue that it's odd ...

Except that 0 and an odd are still odd.

So 0, being even without behaving like an even number, is rather odd.

### Pedophile (1)

#### Profane MuthaFucka (574406) | more than 3 years ago | (#34668690)

n<18 is prime

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