Correction ... unoconv listener for Ubuntu 16.04 could be used with CentOS 7 (not 6).
That has to do with Annotation of assignments.
Rather than me re-writing ...
https://docs.moodle.org/31/en/Assignment_settings
https://docs.moodle.org/31/en/Assignment_FAQ
Then again, you teach math/science and your ISD has Google Docs/Drive ... is that correct?
Would think you could find something a lot better via Google .... depending upon assignment and how students are submitting + how you grade ... or where your official gradebook (for the entire school) resides.
Yeah ... I know that's clear as mud. :|
'spirit of sharing', Ken