The Resulta BS 9  were made in the mid 1900s in West Germany. 

This adding machine were invented by Paul Bruning, and is capable of both addition and subtraction.

Paul Bruning's diminutive Resulta 9 is an advanced type of rotary disc adding machine, similar to the AMCO / Todd Protectograph 'Star' adding machine from 1917. Exposed on the face of the Resulta 9 are nine ratcheting toothed discs which are set with an included stylus. The stylus is placed in the selected column, in a depression adjacent to the number to be entered, and the disc is rotated downward until the stylus stops at the bottom of the column. The bottom register displays the last entered value, while the top register displays the accumulator. 

New input is immediately applied to the accumulator as it is entered. An input control bar at the front of the machine is depressed to reset the discs and display register, and can be set to instantly reset with a locking lever located on the right side of the machine. When the input control bar is set to immediately reset, the Resulta mechanism becomes completely indifferent as to the order in which digits are entered. For example, the calculation of 123+456+789 can be entered as 3-1-2-6-4-5-9-8-7, or 1-4-7-2-5-8-3-6-9, or any other possible combination. 

Unlike the earlier Star adding machine, which relies on the addition of complements to perform subtraction, the Resulta 9 performs direct subtraction with a complementary accumulator, and is capable of subtracting below zero. The Resulta 9 is also much smaller than the Star, but its small size requires the use of a stylus while the Star can be operated with a finger.