Go to the "Settings" tab (to the right of "Description") within this widget and click the "Add formula" button
Specify the name of the formula, assign the order of calculation, and also write your formula.
To substitute values from the field into the formula, insert "@" and select from the proposed list.
As part of the formula setup, you can specify the formula execution conditions under which this formula will work.
In the "Reference" section, you can add numerical values to the selected values in the fields of the list / multi-list / flag / radio button type
To substitute values in the formula based on the directory, insert "#" and select from the proposed list