What is the unit of camera film?

The unit of ordinary camera 135 film is one film, so Quan Huafu film camera is allowed to use 135 film for 36 films and half-frame camera for 72 films. A roll of 120 frame film is 12 (the imaging part is 6CM high and 72CM in total length, that is, 6X6 is 12, 6X7 is 10, and 645 is 16). If it's 135 film, an ordinary camera will do. There are many units of film, one frame is equal to 1/2 135, and the time is also 24 frames per second (a roll of 135 photographic film is only 3 seconds long on the film machine). The above is personal information. Please correct me if there are any mistakes.