Ever wanted to open / edit and save MS Office documents without the need of Office 365 installed.
All you need is to have Chrome installed on your machine and add the MS Office Editing extension.
1. Copy an Excel for to your Gdrive or go to https://drive.google.com and upload an MS Office file.
Once the XSL(X) file is uploaded, open it with Google Sheets, in this case.
2. Open the file and make some changes.
You will see now 2 files, the original and the new Google Sheets file.
The beauty is that you can work simultaneously on the file with multiple users !
The Original MS Office file you can open with Google Drive Viewer
3. Next download (save) the file again using the original XLSX Office file extension.
4. Open the new XLSX file in MS Excel, and check the result.
Works like a charm !
More information can be found here : View and edit Office files in Google Docs, Sheets, and Slides