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
ROMAN ABACUS
Ancient bronze abacus used by the Romans. This is now in the British Museum
arithmetic . Indeed , practically everyone who did any work with numbers had at hand a small box or bag of these calculi .
Sometimes the merchants used a little calculating machine called an abacus (ab'à kus) in which the calculi moved in grooves.
NUMBER STORIES
While Caius was learning to add and subtract with the Roman numerals and with calculi , a Chinese boy , whom we may know as Wu (woo), was learning to add and subtract with the numerals which Chang had studied many years before . He too found it necessary to use something like the calculi which
ANCIENT CHINESE STICK NUMERALS
The number 1267 expressed by means of rods or sticks by the old Chinese method
Caius had worked with, but instead of pebbles or small disks he used rods made of bamboo. Wu thought he was doing something remarkable if he added two large numbers in two minutes. You would probably add them in a few seconds, but think how much longer it would take if you had only a little pile of sticks with which to work. It took Wu some time to lay the sticks out to represent a number and still longer to represent two numbers and then to find their sum.
OF LONG AGO
This plan of computing by bamboo rods was carried by the Chinese to Korea, but
KOREAN RODS
Computing rods made of bone . Until quite recently these were used in the schools of Korea . The numbers were represented somewhat as the Chinese numerals were , as shown on page 52
the Koreans used rods made of bone , and continued to do this in their schools and in business calculations until quite recently.
NUMBER STORIES
It was more than a thousand years after Wu learned to add with the bamboo rods that the Chinese adopted the old Roman idea of having the calculi fastened to an abacus , and so they invented their reckoning board ,
CHINESE ABACUS
Chinese abacus, or suan pan. This instrument is used everywhere in China to-day
or suan pan (swän pän). This they use in the schools, banks, and shops throughout all of China even to this day, and they often calculate more rapidly in this way than we can with pencil and paper. You have probably seen the suan pan used if you have ever visited a Chinese laundry in any of our cities.
