> Yes - it boils down to “there are 10 cards. Pick some number of cards, give me the rest, and I’ll tell you how many you picked”. It boils down to that when y

> Yes - it boils down to “there are 10 cards. Pick some number of cards, give me the rest, and I’ll tell you how many you picked”. It boils down to that when you know the trick, but it isn't trivial to conclude that from just seeing the trick being performed.