Can I pass a reference to a custom column creation

Hi there, sorry just one more thing.

I am trying to pass w parameter or refernce for creating custom table. Is it possible ?

Ua case:

From previous problem which I had I am able to find the column Header name which I want to pass to the Next Custom Column Condition.

By Passing the Coulmn header name which is recivied by the function I need to make a math function over the data from this colum.

Initally I wanted to use a Query :

= let
Source = @#"Table",
ColumnName = #"Dynamic_ColumnName",
#"Added Conditional Column" = Table.AddColumn(Source, "Test Score", each if ColumnName <> "" then ColumnName/12 else null)
in
#"Added Conditional Column"

but I see in the reference there is only Column Header Name provided instead values so I'm getting error:

We cannot apply operator / to types Text and Number

Any suggestions ? Thank you.