> There were four modules where they would do some reading, work through some example problems through interactive software, and then have some homework to work through that was almost identical to the examples.

This just does not look like a universally effective way of teaching to me, irrespective of the topic. It's hardly any wonder that some people fell through the cracks if they were unfamiliar with the subject in the first place. What about leveraging stuff that's actually been tried and tested, like the Khan Academy videos and their automated interactive, school-like environment?