In the video, a man is standing in front of a whiteboard and writing a mathematical equation. He is wearing a yellow shirt and has a black cap on his head. The whiteboard has several mathematical expressions written on it, including the equation he is currently writing. The man is using a marker to write the equation, and he appears to be explaining the process as he writes. The video is shot from the side, so we can see the man's profile as he writes. The whiteboard is the main focus of the video, and the man's actions are the primary activity.