How to add real numbers to the dropdown list?

Question

excel

The bottom line is that when enumerating, for example , 0.1 , it turns out that I add both 0 and 1 . And I need exactly 0.1 0.2 , and so on. Commas, it turns out, are accepted as separating the elements of lists.
I found only an option - add them to other cells, and take the range from there, but this is somehow not optimal.

Answer 1

If you are ready to switch to the number format with  a dot as a decimal separator, you can change the table locale from "Russia" to "United States".
PS So-so option, should be more correct.

Answer 2

1) If you do not need a list of values, but only validation, then you can use your own formula:
=ИЛИ(A1=1,1;A1=2,1)
here A1 = "current cell"
2) As already advised above, you can switch to a decimal separator - a dot.
3) Or do not switch to the dot separator, but use the data like this:
=+ПОДСТАВИТЬ(A1;".";",")
here A1 is a link to the cell in which the check takes place