I'd be leary of basing Currency off of ScaledDecimal, especially if there is to be much manipulation of it (such as multiplication or division).  The reason is that ScaledDecimal keeps the representation of their numbers as fractions under the covers - which can results in some odd (and incorrect) results.

 

There is another package (not part of standard Squeak) that could be more suitable as a basis for Currency: FixedDecimal, located at http://www.squeaksource.com/FixedDecimal .  The code isn't very pretty (sorry about that), but it does work for currency.  That is the reason it was originally written - when I started noticing the results of simple mamipulation of my money amounts where wrong.

 

-Chris