# Fun:Proof that all odd numbers are prime

From RationalWiki

An old joke, but one that may be obligatory for this place.

## Contents |

## [edit] Challenge

Demonstrate that all odd numbers greater than 1 are prime.

## [edit] Responses by profession or category

**Mathematician:**3 is prime, 5 is prime, and 7 is prime. By induction, all the odd integers are 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.**Engineer:**3 is prime, 5 is prime, 7 is prime, 9 is a good approximation, 11 is prime...**Architect:**3 is prime, 5 is prime, 7 is prime, the engineers will figure out how to make 9 prime, 11 is prime, ...**Lawyer:**3 is prime. That's our precedent case. And it's even backed up by 5 is prime, and 7 is prime…**MBA:**Tom Peters told me all odd numbers are prime, therefore that will be the corporate direction for prime numbers.**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, ...**Chemist:**3 is prime, 5 is prime... hey, let's publish!**Psychologist:**3 is prime, 5 is prime, 7 is prime, 9 is latently prime but repressing it, 11 is prime, ...**Quantum field theorist using renormalization:**3 is prime, 5 is prime, 7 is prime, 9 is...uh, 9/3 is prime, 11 is prime, 13 is prime, 15 is...uh, 15/3 is prime, 17 is prime, 19 is prime...**College Professor:**3 is prime, 5 is prime, 7 is prime. The rest are left as an exercise for the student.**Confused Undergraduate:**Let*p*be any prime number larger than 2. Then*p*is not divisible by 2, so*p*is odd. QED.**Measure Theorist:**There are exactly as many odd numbers as primes (Euclid, Cantor), and exactly one even prime (namely 2), so there must be exactly one odd nonprime (namely 1). Therefore, all odd numbers other than 1 are prime.**Computer Scientist:**10 is prime, 11 is prime, 101 is prime...**Programmer:**3 is prime, 5 is prime, 7 is prime, 9 is prime, 9 is prime, 9 is prime, 9 is prime, 9 is prime, 9 is prime, 9 is prime, 9 is prime, 9 is prime, 9 is prime...- (The)
**Economist:**Assume 9 is prime... **English Major:**2 is prime, 3 is prime, 4 is prime...**Mythbusters:**Some people think 4 is prime. We divide it by 2 and it*doesn't*explode! Therefore all odd numbers are prime. (*What do you mean "one data point isn't enough?"*)**Cultural Marxist:**The fact that nine is not prime indicates a deprived cultural environment which can only be remedied by a federally funded cultural enrichment program.**Conservative:**What's nine got against being prime? I'll bet it won't allow the pledge of allegiance to be said in our schools either. Also, it wants the terrorists to win.**Creationist:**Only ungodly Darwinists believe One, that which is Unity, is not prime.**Keynesian Economist:**Any quantity can be made prime by introducing more units of fiduciary media**Aschlafly:**All odd numbers are prime. Any other opinion is LIBERAL DECEIT!!! Godspeed!**Austrian Economist:**Any number may be called "prime": it is entirely up to each person's subjective evaluation as to whether a number has been divided fairly.**Rationalist:**The hypothesis that all odd numbers greater than one are prime has stood up to scrutiny. Experimenters distributing clusters of bananas noted a statistically significant elevation in baboon fatalities when the number of bananas is 3, 5, or 7.**Liberal:**It means nothing to say that a number is prime: any number can be redistributed.**Theologist:**God, being omnipotent, can make any number prime if He so chooses.**Fundamentalist:**Every odd number greater than one is prime. For example, consider nine. Since Pi is equal to three (2 Chronicles 4:2 “a molten sea of ten cubits from brim to brim… thirty cubits did compass it round about”), nine is equal to Pi squared — an irrational number. As it is not a composite number, it must be prime.**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.**Climatologist:**Ancient mathematical records suggest that 3 was prime. Based on the clear trend of alternating between prime and non-prime, computer simulations extrapolate that 37,541 will be prime.**New Ager:**All odd numbers — such as the three eyes, the five fingers, the seven chakras, and the nine orifices — are inseparable from the primal unity.**Ken DeMyer:**Gentlemen! A certain search engine whose name begins with "G" has confirmed that the Christian numbers 3, 5, and 7 are certainly prime numbers, and we have just learned that one of youtube's greatest Christian apologists may certainly soon be posting a video highlighting Conservapedia in regards to the possibility that 9 and other odd numbers will be prime too! Operation Vuvuzela Cornucopia will be launched by the Ides of September. Will this be the Waterloo for the liberal idea that not every odd number is a prime number? Stay tuned for further details!*Olé olé olé*!**TK:**3, 5, 7, ...*apply range block*... Sorted.**Hypnotist:**Prime numbers are those not divisible by 2… And you're back in the room!**Right-wing chain email:**^{[1]}

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 jaw 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*.

**RationalWiki:**The numbers 3, 5, and 7 have been shown to be prime. Further odd numbers will be submitted to the mob for up or down voting, and any number receiving~~50~~51 or more "up" votes will be added to RationalWiki:Best of Prime Numbers.**Microbiologist:**3, 5, 7, 11 and 13 are all prime so I guess the problem with 9 is just contamination.-
**Idiot**: 1 is prime. The rest is prime because I'm so smart that I know the rest is prime. -
**God**: I'm omniscient. Thus, all odd numbers are prime. -
**Lunatic**: The little one trilobites are clumsily invisibly pink. One trilobite is proudly shameful o himself. Thus, insect like numbers three four odd are proudly prime, and the evenly evil numbers are primsilly rosy. -
**Ed Poor**: Odd numbers are six feet, six and three-quarter inches. Thus they are prime. **notedscholar:**3 is prime, 5 is prime, and 7 is prime. By rational elimination of the other real numbers, these are the only three numbers, in which case all numbers are prime.**String Theorist:**3 is prime, 5 is prime, 7 is prime, 9 is prime if you add another dimension.

## [edit] See Also

## [edit] Footnotes

- ↑
*Sans*typos, of course.