Do I really have to calculate this in my head? The first calculating machine designers also asked themselves this question. They wanted to build machines that could be used for simple and error-free addition.

The development of adding machines is presented and the functions of the first calculating machines are shown and explained. We then add with an adding machine. Each child is allowed to playfully solve problems with such an original number slide. Although the addiator, the most successful number slide rule of all time, only came onto the market in 1920, the first number slide rules were used as early as 1660.

Finally, we get to know the Addi 7 addition machine, which was invented in 1930 and makes adding even easier.