This machine belongs to the first generation of fully-automatic Madas, the “A” models. It allows fully automatic positive or negative multiplication and fully automatic division with variable or constant factors. Instantaneous automatic transfer of products (a*b*c), also for raising any number to any power. It has, however, a particular technical “weakness”, for a fully-automatic machine, since there is no Dividend-Setup key.
It requires the setting of figures by the small knobs above the Register I, after moving manually the carriage to the extreme right. In the “A” series, only the 20A has also this astonishing lack of Dividend-setup. Therefore, the 20AG can be considered as a simple aesthetic redesign of the original 20A. Seven years later, the 20BG, redesigned according to the specifications of the “B” models, keeps this strange distinctive characteristic.
Just like any other model, without a “Z” feature, the Product Register has a tens carry-over to two places beyond the keyboard capacity.
Among characteristics, there is a lever for disengaging automatic carriage return after multiplication, to facilitate following this immediately with division. It is also possible to have a “split clearance” in product register, enabling individual and accumulated products to be shown at the same time.
By turning the lever over dial 9, automatic clearance can be disconnected from the 8th to the 20th dial in the “Product Register”. If this is done, dials 1-7 will clear themselves, whilst dials 8 to 20 will accumulate in multiplication.