Yes, this is actually quite simple, when you think about it, and obvious, but may be a little annoying to set up.
One way:
Each section can be a Book, everything relative to that book is placed into the book. This creates a single step to multiple topics on a single theme. For example, Algebra Book 1 is Intro, about 5 or 6 pages of pre-algebra. Book 2 is Terms, 3 or 4 pages on like terms, unlike terms and terms and operations. Book 3 Equalities and Inequalities, and so on. This is just one way.
Another way:
Create your course as normal then add all your pre-made pages as a zip file, (include files, images and so on) to the course. In the first section you put in your introduction into the section title and then hide the zip file in there. Unzip it. Then in a label you put in your menu, linking each page into a menu item.
mmm now you got me thinking about it.... The Book option is probably the more immediately sound approach, but... Let me play with it and I will get back to you...
... a little later:
Another way is to create the course, create the menu you want, add links to each menu item uploading files one at a time. There is a few gymnastics you may have to go through with different file types, like .pdf files, not others, html files just load. I didn't test docs or pages, or text files, but I cannot imagine they will be too different.
Be easier to upload a single zip file then unzip it, but may not be possible - still working on that one. bbs...