A Soviet number puzzle.
18:18
squaring the sum of digits
17:56
This problem is everywhere!
13:44
on the growth of a nice recursive sequence
30:38
Solving Wordle using information theory
18:54
Russia HORRIFIED by France's Brilliant Move on Germany - The US has Lost its Dominance on EU?
16:06
The Greatest Mathematician Who Ever Lived
17:20
Using simpler cases to find a solution to an IMO problem
28:28