In this article we study one class of irrationalities whichmay be defined as covergent series with rational coefficients. This class contain a lot of well known constants such as ln 2, ¼, e.t.c. We consider the problem of determination parameters of rational coefficients by rational approximation of irrationality. We deduced the lower and upper bounds and present an algorithm for determination of unknown parameters. Also, we present some results of practical calculations.
