It is common knowledge that when deriving the distribution function equation one must use the expansion of distribution function as the inverse of the per one particle volume series (1/v = N/v). When doing such expansion, one usually restricts himself by the first power of 1/v, or, at best, the second power of 1/v. The question naturally arises: how much is the value of omitted terms and what is their contribution to the properties of a particular thermodynamic system? Specific calculations have not been reported but, as a rule, it is affirmed that their role is negligible. © 2001 IOS Press.