For example, I have the following text:

one
two
three

I can option-click and then drag across the beginning the these lines to insert the same characters to all three lines, e.g. a dash

-one
-two
-three

Is it possible to insert a sequence of numbers? Like:

1 one
2 two
3 three

If this is possible, how about multi-digits? Like:

1 one
2 two
...
...
10 ten
11 eleven

Note that there is a space in front of 1 and 2 in the first two lines.

Are these possible? Thanks!