My IPad mini cannot open Excel files type (xlsx)

More ways to transfer files and access Word documents:

https://discussions.apple.com/thread/4044866?tstart=0

All of the "Office" document editing applications on the iPad have limitations. Best try them out to see if they meet your needs.

DocsToGo

• VIEW/EDIT/CREATE Word & Excel files(Office 2007/2008/2010)

• VIEW PowerPoint, PDF, iWork, Text, .RTF, and more!

• Send & receive attached supported documents using the built-in Mail app

• FREE desktop application with your purchase! Compatible on Win & Mac allows you 2-way file sync with a WIFI connection.

• Open & Edit files within DocsToGo from any 3rd party app that supports the “Open In” feature

• Supports iTunes File Sharing via USB cable for manually moving files

https://itunes.apple.com/us/app/documents-to-go-office-suite/id317117961?mt=8

Thanks to Texas Mac Man for pointing to this link.

"Quickoffice Connect Mobile Suite and Documents To Go These two apps share an important feature: unlike Numbers, they can open, edit, and save an Excel spreadsheet without stripping out any data or formatting, even though they can’t display or edit all the existing information; spreadsheets can make the round trip from Mac to iPad and back safely, without losing anything."

http://www.macworld.com/article/1159958/ipadspreadsheet.html

iWork by Apple

• Keynote
• Numbers
• Pages

Office² HD

"Office² HD, the most intuitive and straightforward office document editor available on the iPad, makes it easy to open, view, create and edit Word (DOC & DOCX), Excel (XLS & XLSX), and PowerPoint (PPT & PPTX) files right from your iPad!"

https://itunes.apple.com/us/app/office2-hd/id364361728?mt=8

Quickoffice Pro HD

Create and edit ALL Microsoft® Office -- document, spreadsheet, and presentation formats, as well as view PDF files, on the go. Our advanced file manager lets you manage local files, access Google Drive or other cloud accounts, and works with your iPad email attachments so you can work anywhere, anytime - online and offline.

https://itunes.apple.com/us/app/quickoffice-pro-hd-edit-office/id376212724?mt=8