Olivetti Tetractys 24

Tetractys, equipped with a dual totalizer and several additional features, represented the worldwide state-of-the-art mechanical calculation of those years. Introduced in 1955 and produced until 1966, this calculator was a top-of-the-line model in Olivetti's esteemed MC-24 series. With its mechanics designed by Natale Capellaro and bodywork by Marcello Nizzoli, the Tetractys 24 was presented as a prototype at the Milan Fair in 1955 before its market launch. This calculator distinguished itself with two totalizers, enabling it to perform side-by-side calculations, partial and general totals—a feature that made it stand out as an all-in-one computational tool. Its capabilities extended to sums, subtractions, multiplications, chain and constant factor multiplications, and divisions. A notable innovation was its mechanical "memory," which allowed the storage and recall of numbers for subsequent operations without re-entering data, aiding in complex tasks like the calculation of square footage and cubic volumes. The Tetractys 24 was a commercial success, attributed to Capellaro's excellent mechanics and Nizzoli's aesthetic design. It cemented Olivetti's reputation in the global market of mechanical calculators, following the success of the Divisumma 14. Priced at 485,000 lire. Approximately 150,000 units were produced over its decade-long production run