Abacus – A Life Skill
The methods of addition and subtraction on a Soroban are basically the same as the equivalent operations on a suanpan, with basic addition and subtraction making use of a complementary number to add or subtract ten in carrying over.
There are many methods to perform both multiplication and division on a Soroban, especially Chinese methods that came with the importation of the suanpan. The authority in Japan on the Soroban, the Japan Abacus Committee, has recommended so-called standard methods for both multiplication and division which require only the use of the multiplication table. These methods were chosen for efficiency and speed in calculating.
Because the Soroban developed through a reduction in the number of beads from seven, to six, and then to the present five, these methods can be used on the suanpan as well as on sorobans produced before the 1930s, which have five “earth” beads and one “heavenly” bead.
Despite the popularity of calculators, the Soroban is very much in use today. The Japanese Chamber of Commerce and Industry conducts examinations which Soroban users can take to obtain licenses. There are six levels of mastery, starting from sixth-grade (very skilled) all the way up to first-grade (for those who have completely mastered the use of the Soroban). Those obtaining at least a third-grade license are qualified to work in public corporations.
The Soroban is taught in primary schools as a part of lessons in mathematics because the decimal number system can be demonstrated visually. When teaching the Soroban, teachers give song-like instructions. Primary school students often bring two Soroban to class, one with the modern configuration and the one having the older configuration of one heavenly bead and five earth beads.
Many Soroban experts are also proficient in mental calculation, known as anzan (“blind calculation”) in Japanese. They do this by mentally visualizing the Soroban (or any other Abacus) and working out the problem without trying to figure out the answer beforehand. This is one reason why, despite the advent of handheld calculators, some parents send their children to private tutors to learn the Soroban. Proficiency in Soroban calculation can be easily converted to mental arithmetic at a highly advanced level.
The Soroban is also the basis for two kinds of abaci developed for the use of blind people. One is the toggle-type Abacus wherein flip switches are used instead of beads. The second is the Cramner Abacus which has circular beads, longer rods, and a leather back cover so the beads do not slide around when in use.
Source : Wikipedia