Using skybow forms you can use expressions to calculate field values.
If you want to calculate with numbers having fixed decimal places, but want to make sure you can easily deploy it on another site having different regional / localization settings, it's not solid to use the .toFixed() function.
The toFixed function always returns the number with a "." as decimal separator. However, in a German site the decimal separator should be a ","
It is better to use the .toLocaleString() function, where it's possible to pass the culture name which returns the correct separator and the number will be correct.
The fixed decimal places should be configured on the column but also in the expression as follows: