Wilson's theorem

Episode 5.

Wilson's theorem. For any prime number $p$, the number $(p-1)! \equiv -1 \pmod{p}$.
The video contains the proof.

The same video on youtube:
https://youtu.be/m9Rr5gLVCmM

The blog on substack:
https://mathematicsexplainedandclarified.substack.com