Problems First: Failure Being Productive

The intuition behind solving problems first is also self-evident: how can you learn to solve problems yourself if you are always told exactly how?

Activation of prior knowledge. If you already have some knowledge of how to solve a problem, directly trying to solve it will force you to try to retrieve that knowledge.  

Conceptual understanding. Seeing a problem first may make it easier to understand the conditions where the solution applies. 

Motivation and engagement. Students may tune out if they only study worked examples. It’s impossible to solve a problem without cognitive engagement