How to use the Schickard calculator

In recent years, a number of Schickard calculator replicas have appeared both in various museums and private collections. For the owners of these calculators, and for others, it may be interesting to learn how to operate them. The calculator is composed of the following units: the multiplication unit, the adding machine and the memory unit. These three units are independent of one another; they are not mechanically interconnected. The calculator provides the means to perform the following basic operations: multiplication, addition and subtraction.