The purpose of this paper is to contribute to development of research tools for observation and analysis of educational practices used by teachers in preschool classrooms. More specifically, we approached the implemented curriculum of mathematics in Greek preschool education. We analysed the recorded data from a week of teaching practices in eight classrooms of Greek public kindergartens, based on Bernstein's theoretical framework on pedagogic discourse. The results showed that the actual educational practices in the observed classrooms deviated from the objectives of the official new cross-thematic curriculum for teaching mathematics in Greek kindergarten in terms of the form of transmitted mathematical knowledge, the instructional rules and strategies that teachers adopted for teaching mathematics, and the teaching-interactive relationships between preschool teachers and students.