50g

I checked out your loops tutorial.  It looks pretty good so far.  I understand just about all of the basic programming structures now, well enough to start making some practice programs.  Nancy VonEssen suggested a website at Thiel College.  It looks like they actually have a calculus program there i.e. they know something about math.  A found a wealth of information there.  I have tons of information from them and I think it would help you out a lot.
Go to Files / Rick Wendels Downloads and Notes, Downloadable PDF's & WORD 2007 files / Double click the web address, copy it and paste it into your search bar / Download the PDF called, HP50G Calculator Tutorial with Math Lesson - Theil College.  Its in the Homemade Tutorials Folder.