The key is the embedded spreadsheet on each lesson (much like the web-based code editor). There would be fill-in-the-blank, error fixing, and formula-building type problems and puzzles using the spreadsheet. Once the spreadsheet inputs have been submitted and verified is correct, the site moves on to the next lesson.

How difficult is something like this technically? (please bear with me, I'm non-technical)
Any help is much appreciated - let me know if you have questions.
Thanks!






