We use a Google Form for registration for our charity road race.  I need to have two fields that contain formulas so people registering do not have to do the calculating.  They can order t-shirts.  Cost per shirt is $15. I need the next field to calculate the money they owe, so they don't make mistakes (i.e., 4 shirts x $15 = $60).People can donate additional money so I need a field that will add the amount owed for t-shirts with any additional money donated, and reflect the grand total owed.Is this possible?  If not, do you have any suggestions for a way to do with with another application?  Can forms like Google Forms be created with Microsoft Excel?
Can I have formulas in a Google Form, not just the worksheet?
google forms;formulas