Curta has a compact cylindrical design which will fit in the palm of your hand. It was used to perform addition, subtraction, multiplication, division, and with more difficulty square roots and other operations. It was affectionately known as the \"Pepper Grinder\" due to its shape and means of operation. It would literally grind out answers.
The revolution counter had 605 mechanical parts. Numbers were entered using slides (one slide per digit) on the side of the device. The result counter appeared on the top. A single turn of the crank would add the input number to the result counter, at any position, and increment the revolution counter accordingly. Pulling the crank out slightly before turning it would perform a subtraction instead of an addition. Multiplication, division, and other functions required a series of crank operations. The Type I Curta had 8 digits of slides, a 6-digit revolution counter, and a 11-digit result counter.
During the 1960s, \'70s and into the \'80s Curta was popular among contestants in sports car rallies. Long after the introduction of the electronic calculator for other purposes, they were used in time-speed-distance (TSD) rallies to aid in computation of times to checkpoints, distances off-course, etc