The generalized modus ponens deals with the problem of inference in an imprecise setting. The paper explores four of the most often encountered possibilities, in the case where a single rule is considered at a time. The behavior of two deduction systems sufficient for practical use is investigated in the situation where the dependency between antecedent and consequent variables is described by a collection of rules. It is shown that one can get a meaningful approximation of what is produced by the generalized modus ponens technique. This paper suggests one more step to computational tractability of the fuzzy set theory framework.