The first-level title is 1, 2, 3 ... (numbers only)

The secondary titles are 1. 1, 1.2,1.3,2.1... (1decimal point).

The third-level title is1.1.1.1.2.1.1.2.2 ... (two decimal places).

There are no four-level titles. If there are other parts, please enclose them in brackets.

At other times, if sorting is needed, just press: 1, 1, (1).

Matters needing attention in serial number

First, Arabic numerals are followed by black dots;

Second, there is a pause after Chinese characters and numbers;

3. Use commas after "first", "second" and "third";

Four, the serial number in brackets and the serial number in the circle, no longer followed by pause, comma, etc.;

5. "Part One", "Chapter One", "Section One" or "One" do not need punctuation marks, just leave a Chinese character position between them.

Six, before and after the digital serial number generally no longer use other bullets.

Reference to the above content: Baidu Encyclopedia-Serial Number