There is a setting in the properties of a numeric input field for decimal spaces. Please refer to the page in our help documantation about numeric inputs: /Documentation/manual/html/?fl_numeric_input_properties_refer.htm
I am a bit confused by “A spot for defining the result”. The field to hold a table column total is usually best placed under the subject table, but it doesn’t have to be. The sum of a table column can be set into any field.
The source of the calculation does not matter. If the total field only allows 2 decimal points the value in the total field will only have 2 decimals.