Hi @anon35856144,
Find your documents in “Created by me” section, to my personal opinion this should have been placed at first 
Obviously the files in “All docs” that DO NOT belong to you, you can not delete.
These files are NOT be available in your Google drive 
In case the owner gives you the rights, you can copy the doc and then this copy belongs to you.
This copy, will be available in your Google drive and you will be able to see the formulas and accordingly you are allowed amend it.
Kind regards,
//JP