In this page I would like to feature some content that personally helped me develop as a mathematician and as a computer scientist.

For young kids:

The show Cyberchase - I don't hear many people talk about this show, but I remember it vividly and it made me interested in mathematics well before I even started first grade. I am not quite sure about how it holds up, but I would recommend it for small children.

For teens and up:

Besides Mathematical Olympiads and other contests like the Mathematical Kangaroo, I recommend checking out Projeto Delfos and treetree2, in which I participated mostly as a student and as a collaborator respectively. 

I also recommend the following YouTube channels, the first of which I have watched since I was around 10 years old:

• Numberphile - perhaps the one that needs the least mathematical knowledge, so I would recommend it for younger folk;

• Veritasium - topics are much broader than mathematics, but the mathematics videos hold up, although they might be harder to follow than the average Numberphile video;

• Stand-up Maths;

• MathPunk - a personal friend of mine with videos in Portuguese;

• Vsauce - features math videos less often than Veritasium, but they are still worth a watch;

• Kuvina Saydaki - features math and other topics;

• Purple Mind - this features more advanced topics, so I would recommend some carefulness for those on the younger side;

• Another Roof - similar to Purple Mind but more approachable;

• 3Blue1Brown - a classic one that I would recommend to everyone nearing university;

• Tom Scott - only a small fragment of his videos are CS related, and fortunately there's a playlist I can link directly to. I would still recommend the rest of the channel but not if you're looking for math or CS videos;

• jan Misali - a bit of an odd one out, as it focuses mostly on linguistics and random trivia, but it also features some rather interesting math-related videos.

Furthermore, I recommend the following videogames:

• Professor Layton Series - A series of games featuring all kinds of logic puzzles;

• Baba is You - A game featuring often rather tricky logic puzzles, on the harder side.

For competitive programmers:

My biggest recommendation is to try different problems. I personally believe the quality of the ONI problems is rather good, but afterwards you should aim higher towards IOI problems. As a book I personally recommend the Competitive Programmer's Handbook.