I am able to define a rule that has multiply or divide operators in some cases using "Return Value Restriction", where I can relate a field and a parenthesized expression using a relational operator; i.e.: <field> <op> ( <expr> ). I, however, am looking for the usage of functions in Guvnor in some cases, e.g., how to define a function within Guvnor and use it in a technical rule?. There seems to be very little documentation about the function usage within Guvnor. satjo wrote: -- View this message in context: http://www.nabble.com/multiply-or-divide-functions-in-rules-Guvnor-tp2591... Sent from the drools - user mailing list archive at Nabble.com.