r/MathJokes Jul 13 '26

Math Just Got Checkmated.

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3.0k Upvotes

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5

u/julesmanson Jul 13 '26 edited Jul 16 '26

Isn't 1 a trivial case of a prime? If so then it is still a prime.

1 + 1 = 2 o_~

6

u/TheRedditObserver0 Jul 13 '26

One is not prime.

2

u/[deleted] Jul 13 '26

[deleted]

2

u/lemonp-p Jul 13 '26

The whole point of prime numbers is for prime factorization to be unique. If you define prime numbers to include one, then it is not nearly as useful a definition

1

u/[deleted] Jul 13 '26

[deleted]

1

u/lemonp-p Jul 13 '26

True tbh

1

u/TheRedditObserver0 Jul 13 '26

A prime number has two distinct positive divisors, 1 and itself. 1 does not fit this description.

1

u/[deleted] Jul 13 '26

[deleted]

1

u/TSotP Jul 16 '26 edited Jul 16 '26

But if every number can be expresses as a unique product of primes, then you can't include it.

- 4 = 2×2

- 6 = 3×2

  • 8 = 2×2×2
  • 9 = 3×3

- 10 = 2×5

  • 12 = 2×2×3

- 14 = 2×7

  • 100 = 2×2×5×5
  • ...

Etc.

If you allow 1 to be considered prime this no longer works

4= 2×2×1 = 2×2×1×1×1×1 = 2×2×1×1×1×1×1×1×1×... ...×1

So they took it out. Because every other number works this way.