Editing Curta (section)

== Design ==

The Curta's design is a descendant of [[Gottfried Leibniz]]'s [[Stepped Reckoner]] and [[Charles Xavier Thomas|Charles Thomas's]] [[Arithmometer]], accumulating values on cogs, which are added or complemented by a [[Stepped Reckoner|stepped drum]] mechanism.

Numbers are entered using slides (one slide per digit) on the side of the device. The ''revolution counter'' and ''result counter'' reside around the shiftable carriage, at the top of the machine. A single turn of the crank adds the input number to the result counter, at any carriage position, and increments the corresponding digit of the revolution counter. Pulling the crank upwards slightly before turning performs a subtraction instead of an addition. Multiplication, division, and other functions require a series of crank and carriage-shifting operations.