Adding the value of two fields

Hi Guy,

Is it possible to add the value of two fields and set the result in another field in business process. For example

Amount  =  [#Read  Main Product data .First item of resulting collection.Price#]+([#Read  Main Product data .First item of resulting collection.Non-Recurring Amount#]-[#Read  Main Product data .First item of resulting collection.Non-Recurring Waiver Amount#]).

Thank you.