alt Hacker NewsAs that link says, this approach is used in Maths textbooks, and yet, as the parent of two kids, I have never come across a single student who is able to pass trig without working the problems.
If reality differs from the results of academic studies, it's not the reality that is wrong.
The worked-example effect doesn't say that worked examples replace exercises. It says that worked examples prior to exercises beats exercises alone.
There's a section on that page about faded worked examples:
> "In order to facilitate the transition from learning from worked examples in earlier stages of skill acquisition to problem solving in later stages, it is effective to successively fade out worked solution steps"