As stated in one oldbook "Adding machine" (authors Evdokimov, Yevstigneyev,Kriushin) multiplication and division on the iron calculator (famous "iron Felix" - see above) isa 4- 5 timesfaster thanin the "wood calculator" (see above) but the addition andsubtraction -1.3- 1.7times slower.
Isaw inmy youthon the table of bookkeepers both suchcalculators- an Ironfor multiplication and division and a wood - for addition and subtraction.
The most interestingactionon the ironcalculator -a divisionby zero.The manquicklyguessed thatit is not possible and stoped turning the handle. Butthen (middle ofthe last century) arithmometerswith electric drive came... I heard that one suchelectricarithmometer is doing this devision to present time
I sawlast autumnin one storein Germany (Zittau) this cash register (see below).He wasat work!
The sellergave me thepossibility to payformy purchase with this device!
