Number with comma

[Diogenes_ASBL_V]

I have a rather simple question, but I can’t figure it out

I have a column where I want to store numbers with a comma, for example 0,5

Now I can’t get the format right.
I can only store whole numbers and no comma numbers.

What am I doing wrong?

These are my settings:

[Steve]

Should be Decimal.

[Diogenes_ASBL_V]

Thx Steve …