There is the so-called [FCI test][1]. It contains a list of questions such that anyone who can speak will have an opinion. Based on the answers one can determine if the person knows elementary mechanics. I learned about this test from the [lecture of Eric Mazur][2], which is an interesting lecture, and it describes an application of such a list. It seems that there are no analogous tests in mathematics. Or did I miss something? Sergei Tabachnikov shared a couple of questions that might work: * One needs to peel potato. What is faster and why: peeling a pound of large or small potatoes? * Why does the reflection in the mirror interchanges left and right, but not up and down? * Two persons are walking down an escalator (that is moving down), counting their steps. Who will count more steps, the one who is moving faster or slower? >Could you share more questions of this type; please make one question per answer. [1]: https://en.wikipedia.org/wiki/Force_Concept_Inventory [2]: https://www.youtube.com/watch?v=WwslBPj8GgI