(music theory) how are the numbers counted ... for example: 1-2, 3-4, 3-5, 2-7, how are these numbers calculated?

The number of tones refers to the number of semitones or whole tones contained in an interval. Interval numbers are marked with fractions, integers and bands. The number of semitones is 1/2, and the number of whole tones is 1. In order to distinguish the intervals with the same series but different numbers, words should be used to explain them. For example: pure level 1: C-C D-D small scheduling, the number of notes is 0; E-F #F-G scheduling with the number of notes 1/2; Degree C-D E-#F small degree, note number1; However, the third degree of C-D E-# F small schedule /2 with a tone number of 1 is three degrees larger than that of E-G F-bA: the third degree of C-D-# F with a tone number of 2 is pure four degrees; C-F F-bB with notes of 2 and 1/2 increases by four degrees in the fourth degree; And the fourth degree of F-B C-# with a note number of 3 is added. F minus five degrees: five degrees B-F C-bG notation three, pure five degrees C-G B-#F notation three and 1/2, small six degrees E-C #F-D notation four and six degrees C-A # D- notation four and 1/2. Seven degrees in b minor: seven degrees with five notes-seven degrees in f C- bb major: seven degrees with five notes and 1/2 C-B D-#C pure octaves: a group of octaves with six notes-a group of small characters.