The clearance of a decimal pascaline
The movie shows the clearance of a decimal pascaline. At the beginning, all the windows are forced to "9".
The operator sets the various numeral wheels to “9” without mental calculation. The only thing to be made is to put the stylus between the marked rays and to turn until the stop.
Then "1" is added in the unit position, a sequential carry occurs from the right to the left and "0" is displayed in all the windows. The distinction between this replica and a pristine pascaline is that the slide cover must be moved toward the operator to set the machine in the addition mode.