Timothy Gowers solves Question 5 of the 2025 International Mathematical Olympiad in real time. The questions can be downloaded in different langiages and are summarized on the IMO site (linked below). It is instructive (and entertaining) to follow the reasoning of an expert solving a mathematical problem. Of course, you can (and should) stop the video here and there and try to solve the problem yourself. Whenever you are stuck for a longer time, you may watch a little sneak preview. Mathematics is more of a marathon than of a sprint.
International Mathematical Olympiad International Mathematical Olympiad 2025 Problems Timothy Gowers WP: Timothy Gowers