You’re free to use whatever numbering scheme you want as long as it gives the correct output. **There is no preferred way that I know of, and this is good** – needlessly limiting people’s ability to produce the desired output serves no purpose and can even be harmful: Too many rules alienate users from writing posts, and that’s definitely *not* what we want.

As the output shows, there is absolutely no difference between a list numbered with any 0 or 1

    0. 
    0. 
    0. 

and a list using the actual numbers that appear in the output as well:

    1.
    2.
    3.

The first number you use is the starting number for the list (but both `0` and `1` give 1), so to begin with 4 you could do `4., 5., 6.` or `4., 4., 4.` or even `4., 0., 10.`, the output is the same. In the case of your answer the editor just [wasn’t fully aware your syntax was fine](https://meta.askubuntu.com/questions/17926/what-is-the-preferred-way-to-add-a-numbered-list-using-markdown/17928#comment37654_17927).

Ask Ubuntu’s [formatting help page](https://askubuntu.com/help/formatting) is *a single page with everything* you need to know about markdown by design; let’s keep it as simple as possible. It says:

> A numbered <ol> list:
> 
>     1. Numbered lists are easy
>     2. Markdown keeps track of the numbers for you
>     7. So this will be item 3.

I’d say this means essentially what I wrote above: Output matters, the rest is up to you.