Google Drive’s Docs, Sheets, and Slides apps are scheduled to cease supporting exports to Microsoft’s older Office 97–2003 formats at the end of the month. According to the Google Apps blog, In September, we added the ability to export Google documents to the newer Microsoft Office formats that rely on open standards (.docx, .xlsx, .pptx). […]
The Google Drive mobile apps for Android and iOS now allows users to create and view spreadsheets: Previous versions had allowed creating and editing of documents but only viewing of spreadsheets created elsewhere. For more information and links to download the appropriate apps, see here.