Reading Lee Harris - I was surprised to be reminded that learning basic concepts - rational vs. irrational numbers, transcendental numbers, etc. is very different now than 150-200 years ago. We let our students to trust that the power of the irrational number set is greater than the power of integer set. This is very counter-intuitive fact. It becomes obvious if you try to discover yourself the concept of power of sets. Let a student to repeat Georg Cantor's way.