There is a gap between program languages theoreticians and practical programmers: the former are strong in science of Abstract Algebra and Formal Logic, the later – in the craft of software development. The paper sketches a very simple approach to algebraic and logic foundations of formal program semantics classification, an approach that should fit practical programmers just with rudimental experience in logic and algebra. In particular, paper presents operational, denotational, axiomatic and second-order semantics for a toy language (that just looks like a programming language).