Help Writing a Forumla

Help Writing a Forumla

I need help writing a simple formula.  It needs to be a currency field that is derived from 2 fields (Both of which are currencies)

The formula would read

(ARV *.65) - (Estimated Repairs)

"ARV" and "Estimated Repairs" are the names of my custom fields. Ive attached a screen shot to show you the fields in my CRM.

I hope you can help. Im such a neophyte when it comes to this!!
Thanks so much