|When the Laboratory for Mathematical Machines was established in Prague in 1952, one of its key proponents, next to the chief designer Antonín Svoboda (1907-1980), was professor of applied mathematics in Prague, Václav Hruška. Pioneers in computing machinery in Czechoslovakia expressed their thankfulness for his moral support by naming the lecture room Hruška’s aula. Václav Hruška (1888-1954) worked in numerical mathematics (or rather practical mathematics, as it was then called in Czech), initially with his senior colleague Václav Láska (1862-1943). Václav Láska studied mathematics and physics, but his work mainly concerns using mathematics in calculations in astronomy, geodesy, and seismology. Together, Láska and Hruška published Počet grafický a graficko-mechanický (Graphical and mechanical calculus) in 1923 and Theorie a prakse numerického počítání (Theory and Practice of Numerical Calculations) in 1934, two key monographs on the topic in Czech. Hruška also had a collection of machines used for calculations. As Hruška explained in a reworked version of Počet grafický a graficko-mechanický (Graphical and mechanical calculus), published in 1952, the graphical methods were exploited and now the only significant improvement can be hoped for through the use of machines. In my talk, I will explore the various practices in calculation as proposed by Láska and Hruška.