ActiveMath is a Web-based intelligent learning environment for mathematics. One of the major components of ActiveMath is a subsystem for interactive exercises. In order to allow for intelligent diagnosis of learner's answer in an exercise step ActiveMath remotely connects to external mathematical reasoning services. This diagnosis is used for instant updating of the Learner Model of ActiveMath with the current mastery values of the learner w.r.t. the domain concepts he learns as well as it serves as a basis for providing adaptive feedback to the student. We describe the framework of semantic evaluation services of ActiveMath, and the generic format for queries to such evaluation services which are specifically oriented to facilitate diagnosis and feedback generation in interactive exercises.