I addressed my son's class in school when he was five. it was not quite the same thing as what you're asking about: it was part of a series of "what I do at work" talks by parents, and it was very brief. I wanted to give a little taste of topology. Of course I prepared a big Moebius strip and did tricks with it. I considered also counting $v-e+f=2$ for some convex polytopes, but I decided to keep it simple, so as not to overreach or overstay my welcome. So instead I drew an octagon on the chalkboard and had them discover that this thing with eight sides also has eight corners. And when that had sunk in I remarked that if I had drawn something with one hundred sides, it would have had one hundred corners. One excitable little boy shouted "Do it! Do it!" So, one conclusion: yes, they do like big numbers.