Soviet Mechanical Calculator (Odhner Arithmometer)
Drag the levers up/down or click on the track to set digits 0-9. Each lever controls one decimal place.
Set a number, then click + (crank forward). The number is added to the result register.
Set a number, then click − (crank backward). The number is subtracted from the result register.
Set the multiplicand, crank N times for each digit of the multiplier, shifting carriage left between digits.
Set the dividend in result register, set the divisor in input, then crank backward repeatedly.
Shift left for higher decimal places (×10). The counter shows position-weighted crank counts.