Sorry if this has been covered before. I recently bought a Macbook Pro (and loving it) with iWork 09 pre-installed. I really like using numbers compared to office. However, I have just started working in a group where all the other members use Windows with Office 2007. I have been able to save my numbers (and pages) documents as the office equivalent. My problem lies when I am working on a document in numbers that is the office format. I like to continuously save my progress but whenever i press save, I have to save it as a whole new document or replace the existing one. When I used to work in office 2007 I used to just press save every now and then and it would save my changes. Am I doing something wrong or is it because I am working on an excel spreadsheet in numbers (word document in pages)? I hope this makes sense and thank you in advance for any help.