The finite difference methodFinite difference method of discretisation of transportDiscretisation technique equations used in CFD codes is described. This method is based on the application of the Taylor seriesTaylor series and leads to three approaches to finding the algebraic approximationsAlgebraic approximations for theFirst derivative first derivativesDerivative of functions: the forward differenceForward difference, backward differenceBackward difference, and central differenceCentral difference. Also, the algebraic approximation for theSecond derivative second derivativeDerivative of a function is obtained. These approximations were obtained for equal and unequal distances between the points, and the limitations of the finite difference method are discussed. The finite volume methodFinite volume method of discretisation of the abovementioned equations is described. In this method, the domain is divided into a certain number of finite volumes (cells), with no empty spaces between them. The divergenceDivergence theorem is applied to each cell to reduce the integralsIntegral over their volumes to the integrals over their surfaces. The finite volume methodFinite volume method is applied to a one-dimensional problem of finding the distribution of temperatures on a flat wallWall if the temperatures on the wallWall surfaces are given. The temperature values are shown to be the same as those predicted by the analytical solution to the steady-state heat conduction equation.