I think it's more a question that there's no easy solution -- or that there really is a problem. Fractions exist even when you're dealing even in coins; down here, a long while ago it wasn't uncommon to go around with over 1 million in local currency in your wallet. And it wasn't uncommon to receive change in 1000 or 5000 bills. Also, people aren't that bad at figuring math if they hve to. Back when our money lost value from one week to the next, people managed to figure out how much to pay for things. Maybe it has to do with people giving little value to their money, instead?