Looks good, but sleight of hand is more amazing

Message:

The card piles flip over. So the one that limited what he would have left was always then the one to later flip. The trick also has several ask and means nothing, like pick three piles, then pick two more from them.

An ancient Babylonian, using tokens to count sheep, would easily see the trick as no trick. Because he dealt with objects to count always.

We don't, so it seems like magic. As you said math. But more correctly, just using tokens as a memory register.

Yours,