Custom Excel VBA functions for numerical solution of a first-order Cauchy ODE

The current study provides basic formulas for approximate solutions of a Cauchy problem of the first order ordinary differential equations by the methods of Euler, Adams, in which finite differences of the first and secondorder, and Runge-Kutta of the fourth order are applied. The program codes of the VBA Excel custom functions that implement these methods are also provided. These custom functions allow finding approximate solutions to the Cauchy problem for the first order ordinary differential equations online. All custom functions have descriptions explaining their purpose. The use of custom functions is shown in solving specific problems, including when the solution must be found on a finite sequence of equidistant values.