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Using Office Web Apps
With Office Web Apps you can view, edit, and share Word, Excel, and PowerPoint using a web browser. Assignments for your courses must be saved on your desktop, uploaded to course and placed in a folder until you have completed the course
In order to use Microsoft Office Web Apps you need a Microsoft based account such as Hotmail, Live, MSN or Outlook.com.
Learn More: Microsoft Office Web Apps - Getting Started Guide