Notes: "The Addiator Negativ is a duplex slide adder performing addition on one side and subtraction on the other. The two sides are linked so calculations may continue from one side to the other. The “Negativ” name comes from the fact that this will show totals of less than zero, making it very useful for people adding up their profits and, especially, losses. Totals of less than zero are shown in the “Negativ Saldo” windows. Perhaps the cleverest feature of this adder is that it stores its stylus in the clearing handle. What a great way to keep from losing it. I can’t guarantee that was the originally intended way to store the stylus, because I’ve never seen it done before, but the stylus is the perfect length for it, and the wire loop attached to the clearing handle is offset slightly to one side to make room for the stylus. "
