I think iOS 11.1.1 killed Numbers for iPad
I have an iPad Pro 9.7" and use Numbers frequently. After installing iOS 11.1.1 I can not open my Numbers spreadsheet files. I get the message 'the file does not exist'. I can create another new spreadsheet from the templates, and after a few seconds, it too is unusable.
iPad Pro Wi-Fi, iOS 10.3.2, Over 200 Gb available. New iPad.