Unknow colum in Column Expression

Good morning,

I am not practical with colum expression. I am creating a column named “Number_2”.

I want this column to be 1 or the value in cell above of the same column ("Number_2,-1) plus 1. I receive an error of missing column (the one that I am creating).

I would expect the column to be recognize as it should be iterative.

Is there any way to refer to row n-1 of the same column that I am creating?