Edit Excel files in Google Sheets Office Compatibility Mode
http://googledrive.in30minutes.com
New for 2016! If you don’t own Excel, it is still possible to perform limited editing of MS Excel spreadsheets inside of Google Sheets using Office Compatibility Mode. This short video (less than 5 minutes) explains the special Chrome Extension required to use Office Compatibility Mode, and then shows what limited editing functions are possible on a .xlsx file inside of Google Sheets. The narrator is Ian Lamont, author of the top-selling Google Drive & Docs In 30 Minutes.
http://googledrive.in30minutes.com