In this paper we present the operational semantics of RFuzzy, a fuzzy Logic Programming framework that represents thruth values using real numbers from the unit interval. RFuzzy provides some useful extensions: default values to represent missing information, and typed terms to intuitively restrict predicate domains. Together, they allow the system to give constructive answers in addition to truth values. RFuzzy does not confine to a particular Fuzzy Logic, but aims at being as general as possible by using the notion of aggregation operators. Keywords-- Operational Semantics, Logic Programming Application