The following example depicts calculation of height using the inches value (Height) to derive whole feet, then remaining inches - each to populate individual fields on a form.
 
The first line validates that the height field is not empty and then calculates whole feet from the height value in inches. 'SP Ht1' represents the field for height in feet:

if (Event.Fields['Employee.SpouseInsured.Height'] != null) Event.Fields['SP Ht1'] = Event.Fields['Employee.SpouseInsured.Height'] / 12;

The second line validates that the height field is not empty and then calculates the inches remaining after dividing by "12" from the height value in inches using the Modulus operator. 'SP Ht2' represents the field for height in inches. The modulus operator (%) computes the remainder after dividing its first operand by its second.

if (Event.Fields['Employee.SpouseInsured.Height'] != null) Event.Fields['SP HT2'] = Event.Fields['Employee.SpouseInsured.Height'] % 12;

Additional reading:
http://msdn.microsoft.com/en-us/library/ff3sz136(VS.85).aspx