Summer of Math Exposition

Good demonstration of WHY we have the divisibility rules we have. The a_n could be defined for the casual viewer since the idea of “remainder” is explained. This is also a good pattern setting to “discover” divisibility rules for numbers not mentioned or for finding divisibility in different bases.

Very interesting stuff, but a low quality video unfortunately

Very elementary. Good for pupils.

I would just say, add some creativity into the explanation, maybe learn some fancy video editing techniques. The explanation itself was super clear, no real problems with that part. It just could get repetitive as you explain each divisibility trick in a similar way each time.