Page:Smith - Number Stories of Long ago (1919).djvu/74

OF LONG AGO pointed sticks that looked somewhat like our pencils, erasing their work by simply smoothing the wax. They always carried their calculi, however, if they were studying arithmetic. Indeed, practically everyone who did any work with numbers had at hand a small box or bag of these calculi.

Number Stories, p51-illustration.png ROMAN ABACUS Ancient bronze abacus used by the Romans. This is now in the British Museum

Sometimes the merchants used a little calculating machine called an abacus (ăb'åkŭs), in which the calculi moved in grooves. 51