This module gives you the ability to round numbers to either decimal or 
fractional precision while encapsulating the rounding precision in an 
object. This allows scripts and modules to maintain multiple precision 
values as objects.

It also implements flexible scheme parsing, so that your programs and 
modules can offload the how-to-round decisions to this module.

WWW: http://search.cpan.org/dist/Math-Round-Var/