Worked-out examples consist of a problem statement
(e.g., a word problem) and a step-by-step solution procedure, where the application of the
latter to the former is illustrated and explained. In order to help learners extract the relevant
structural features of problems, it has been proven useful to not only provide single
examples, but example combinations. Effective example combinations are characterized
by the fact that examples from the same problem category are embedded into different
cover stories and/or examples from different problem categories are embedded in the same
cover stories (Quilici and Mayer 1996; Scheiter and Gerjets 2005).