Abstract: In this paper a series of approximate formulas for the expression, derivation and integration of functions given by way of n data points is suggested, and in addition, some computational test results are also given. These formulas are derived from so-called "part ideas", so they have many advantages, one of which is the guarantee of convexity. With the aid of a digital computer, they can be effectively used in experimental data processing or fitting, contour designing, approximate derivation, numerical integration, etc.