We used to call them 'Adding Machines' - http://www.vintagecalculators.com/assets/images/Burroughs_1.JPG http://www.vintagecalculators.com/assets/images/Burroug

We used to call them 'Adding Machines' - http://www.vintagecalculators.com/assets/images/Burroughs_1.JPG http://www.vintagecalculators.com/assets/images/Burroughs_1.... They were gradually phased out when (very expensive!) digital hand-held calculators came on to the market in the early 1970s. * Expensive as in a simple 4-function digital calculator was priced at more than half the average person's weekly salary. 10-15 years later, similar-capability solar-powered calculators were being given away as promotional materials.