How to create a calculated field in Redwood UI

Summary:

I created a calculated field in VBS as place holder of the computation of the 2 fields in the layout

logic:

	let CalVal;

	if($fields.TargetValue.$numberValue()>=1 && $fields.ActualValue.numberValue()>=1)

	{

	  CalVal = ($fields.ActualValue.numberValue()/$fields.TargetValue.$numberValue())*100;

	}

	else

	{

	  CalVal = '';

	}
        return CalVal;

i tried using the business rule and it works only if the fields involve are outside the group fields in the layout.

i also tried adding simple calculation in the calculated field default value that i created and it works, but when adding condition as shown above it is no longer working.

code i add in the default value