Some Notes on the Exercise Files
The files can either be html files (with suffix .html) or 'logic' files (with suffix .lgc). The html files are, yes, html, and the logic files are, internally, a mix of HTML and XML (i.e. just text). So, all the files are text (which can be read, typed, etc.). HTML is good enough for most of the functions of Deriver. But if you need to save half-finished proofs with the intention of going back to them, .lgc is required. Similarly, for half-finished trees or diagrams. Deriver can save as .html or as .lgc, and it can open both of these types. The User can choose.
Working Offline
You can open a file in Deriver from an url. Then just save it. This is not the best technique if you want twenty files. Sometimes an entire course-load of exercise is provided here in a single html document or a single zipped folder of the exercises. [Zipped files from any remote source are a security risk. You should scan them with some suitable virus or malware checker before opening.]
Easy Deriver [Sentential and Predicate Logic—Bergmann Syntax]
[Check in the Settings of your Deriver app that the parser is set to 'bergmann'.]
Here are all the exercises. Your easiest way to open one of these is to copy (i.e. don't click on it) the relevant link from below, then use the link in Deriver to 'Open from URL ...' off the Deriver's File menu.
https://softoption.us/test/Deriver/PropExBergmann/PropExBergmann1.html
https://softoption.us/test/Deriver/PropExBergmann/PropExBergmann2.html
https://softoption.us/test/Deriver/PropExBergmann/PropExBergmann3.html
https://softoption.us/test/Deriver/PropExBergmann/PropExBergmann4.html
https://softoption.us/test/Deriver/PropExBergmann/PropExBergmann5.html
https://softoption.us/test/Deriver/PropExBergmann/PropExBergmann6.html
https://softoption.us/test/Deriver/PropExBergmann/PropExBergmann7.html
https://softoption.us/test/Deriver/PropExBergmann/PropExBergmann8.html
https://softoption.us/test/Deriver/PropExBergmann/PropExBergmann9.html
https://softoption.us/test/Deriver/PropExBergmann/PropExBergmann10.html
https://softoption.us/test/Deriver/PredExBergmann/PredExBergmann1.html
https://softoption.us/test/Deriver/PredExBergmann/PredExBergmann2.html
https://softoption.us/test/Deriver/PredExBergmann/PredExBergmann3.lgc
https://softoption.us/test/Deriver/PredExBergmann/PredExBergmann4.lgc
https://softoption.us/test/Deriver/PredExBergmann/PredExBergmann5.html
https://softoption.us/test/Deriver/PredExBergmann/PredExBergmann6.html
https://softoption.us/test/Deriver/PredExBergmann/PredExBergmann7.lgc
https://softoption.us/test/Deriver/PredExBergmann/PredExBergmann8.html
https://softoption.us/test/Deriver/PredExBergmann/PredExBergmann9.html
https://softoption.us/test/Deriver/PredExBergmann/PredExBergmann10.html
https://softoption.us/test/Deriver/PredExBergmann/PredExBergmann11.html
https://softoption.us/test/Deriver/PredExBergmann/PredExBergmann12.html
https://softoption.us/test/Deriver/PredExBergmann/PredExBergmann13.lgc
https://softoption.us/test/Deriver/PredExBergmann/PredExBergmann14.lgc
https://softoption.us/test/Deriver/PredExBergmann/PredExBergmann15.html
If you are comfortable downloading zipped folders, you can download the zipped folders 10 Propositional Exercises (Bergmann syntax) or 15 Predicate Exercises (Bergmann syntax) It is probably wise to inspect any downloaded zip file with some security software. Then, assuming all is well, expand the compressed folders. Then open individual logic files in Deriver using 'Open Logic File' off the File menu.
If you wish to create partial proofs, trees, or interpretations that you wish to save, Save the files As .lgc (html will not save proofs, trees, or diagrams in its format).