To add Formula directly in the Main Form Fields, follow the below link:
‘Control Center’ icon from left menu bar — Select ‘Workflow’ from first Column —
Click on the icon ‘Formula’ from the list of options listed below the workflow.
You will be directed to the ‘Formula’ setting screen.
From the drop down ‘Select the group to identify the field’, select the option ‘Select two column field’.
Then from the ‘Select Field’ drop down select the Form field in which you would like to store the
result of your calcualtion.
From the ‘Field Name’ drop down, select the fields on which you are going to apply the formula.
To apply the formula, select the mathematical operators from the dropdown next to the field names selected.
Click on Save and view the GUI screen to see the formula implemented in your form fields.
To add more Formulas click on the ‘Add Formula’ button.