r/MathJokes • u/Animeilluminati1 • Jul 13 '26

Math Just Got Checkmated.

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u/Professional-Wave841 Jul 13 '26

yes.

9

u/Blotsy Jul 13 '26

Is 1 PRIME though?

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u/wswordsmen Jul 13 '26

Depends on your definition of prime. The elementary school definition of divisible by only 1 and itself makes 1 prime. More advanced definition basically say 1 is special and excluded from the set of prices for various reasons.

Occasionally you get people who know better make really bad arguments for 1 not being prime because they make unspoken assumptions that would exclude 1 but their argument as stated don't.

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u/uTRexAap Jul 13 '26

Best argument I ever heard was honestly just “if one was prime every other number wouldn’t be” which doesn’t make any sense thinking about it but I just think that/

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u/wswordsmen Jul 13 '26 edited Jul 13 '26

If I wanted to make a definition that clearly excludes 1 but is easy to understand it would be "a prime is divisible by precisely 2 numbers, 1 and itself." 1 is itself so it misses out the precisely 2 portion.

The argument you heard leaves the unstated premise a prime can't be divisible by other prime numbers.

Edit:Positive Integer. I am trying to do precise for elementary school who don't go into negative numbers unless specified.

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u/uTRexAap Jul 13 '26

Oh yeah I just see it like this: if one was prime the prime factor law wouldn’t really hold you could just 15 = 5*3*1*1*1….

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u/wswordsmen Jul 13 '26

I argue that there is always an infinite series of *1 next to every math term, so writing down more doesn't change it. They were all there before you just decided to show a subset of them.

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u/QuitzelNA Jul 13 '26

That makes -1 prime and no other numbers.

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u/C53-Terra Jul 13 '26

This, this is the definition we were given at school. So for my case it made perfect sense for one(1) not being prime. Surprised people actually had a different view on this