Right, my point was just that "use pennies" won't work. You have to use fractions of a penny for different tasks. I'm not sure on the implications of using di

Right, my point was just that "use pennies" won't work. You have to use fractions of a penny for different tasks. I'm not sure on the implications of using different fractions at different levels, but I'm sure the problem is more complicated than it sounds. Even before you get into the various methods of rounding that exist.