One *** has 24 keys, 12 major keys and 12 minor keys.

The most common one is the 12-equal temperament mode. Each major key has an affiliated minor key. It uses a key signature and is divided into 12 groups. 6 groups of sharp tones and 6 groups of flat tones. For sharp keys, count up 5 degrees for every sharp you add, and for flats, count down 5 degrees for every flat you add.

Extended information:

The "tune" of music score is the mode, which is a number of musical tones with one sound as the core and different pitches organized together according to a certain interval relationship to form an organism. .

Mode is a form of music organization structure created by humans in long-term music practice. Usually when elaborating on the concept of mode, the central note of the mode, the tonic, is often used as the starting point and end point, and the other notes are arranged in the form of a scale in order of pitch, which is called a mode scale.

In different historical periods, different ethnic groups and regions, various styles have been formed. Various modes have their own characteristics and expressiveness due to their differences in scale structure, the relationship between mode levels, and temperament. The combination of mode and other expression techniques can give music a certain expressive quality and different styles. ?

Baidu Encyclopedia-Music Score

Baidu Encyclopedia-Mode