The objective of this course is principles and methods of financial and commercial calculations. The main attention of course is devoted to interest theory (simple and compound interest theory, force of interest, calculation methods of accumulation and present value of money). Furthermore the course covers calculation methods of annuities. Definition of cash flow, equivalence principle is introduced to students and all acquired knowledge is used to analyse different financial problems. Further the course covers introduction to different types of risks in business, risk classification and risk estimation by applying statistical, expert and special coefficient methods, criteria for decision making and examples of their application. The course covers multicriterion methods of the economic data analysis using statistical software support.