Trick of the game
If the game/app mechanics depend on how well the user understands a concept, ask them how they think you win the game. Use follow-up questions to dig deeper (“What’s the trick to the game?” “You have to get all the points. How do you get the points?”).
Why this technique
This open question allows you to get at kids’ learning without it seeming like a test with one clear right or wrong answer. This can ease kids’ worries about not giving the correct response.