1234567 is pronounced as do, re, mi, fa, sol, la, ti (si in China) in music, representing seven basic steps in the scale.

in the musical system, seven levels with independent names are called basic levels. These seven levels correspond to the sound made by the white keys on the piano now.

Generally, 1, 2, 3, 4, 5, 6, 7 are used to represent scales in musical notation.

the numerical notation is based on the movable roll-call method, with 1, 2, 3, 4, 5, 6 and 7 representing the seven basic levels in the scale, with the pronunciations of do, re, mi, fa, sol, la and ti (si in China), and C, D, E, F, G, A and B in English, with a pause.

the duration name of each number is equivalent to the quarter note of the staff.

Extended information:

There are two marking methods for the names of basic tones, namely, sound names and roll names, and the sound names of each tone are marked by letters. The roll call is expressed by pronunciation.

take c major as an example: from low to high, the names of the basic tones in c major are marked as: c, d, e, f, g, a and b, and their corresponding roll names are seven pronunciations: do, re, mi, fa, sol, la and si.

In the musical system, the marks of the seven basic levels (sound name and roll name) are recycled. That is, after C, D, E, F, G, A and B, they return to C, D, E, F, G, A, B or do, re, mi, fa, so l, la, si, and so on.

Reference: Baidu Encyclopedia-Simple Music.