Nowadays all calculations in building are made in special computational software packages. The numerical computation of difference equations with partial derivatives and integral equations is used in these packages for solving problems of applied physics, deformable solid body mechanics, heat exchange, hydrodynamics and electrodynamics. This method is called finite elements method. Since a field can be divided into the limitless number of elements, there is a question: which amount of them is aimed? In current work analytic solutions of problems of external load influence on elastic half-space are considered: Boussinesq problem of point force and Liav problem of evenly distributed load. Numerical solutions of these problems were obtained in the software package Lira-SAPR 2013. The graphs of radial stresses and or stresses σ_z, ԏxz, ԏyz are plotted. We also made the comparison of the results of analytic and numerical solutions.