Abacus is an ancient mathematical instrument used for calculation. It is one of the world’s first real calculating tools and the early forms of abacus are nearly 2500 years old. The word Abacus is derived from the Greek word, Abax. The early abacuses (or abaci) known as counting boards are different from the modern abacus. It is a brain development tool which helps in exercising the brain and by there improves creativity, concentration, confidence. Thus imparts techniques to do the fast calculation.

Anatomy & Construction

The standard abacus can be used to perform addition, subtraction, division and multiplication; the abacus can also be used to extract square‐roots and cube roots. The abacus is typically constructed with various types of materials and comes in varying sizes. The frame of the abacus has a series of vertical rods on which a number of beads are allowed to slide freely. A horizontal beam separates the frame into two sections, known as
the upper deck and the lower deck.

Basics

The abacus is prepared for use by placing it flat on a table or on one’s lap and pushing all the beads on both the upper and lower decks away from the beam. The beads are manipulated with either the index finger or the thumb of the left hand.

Bead Values

Each bead in the upper deck has a value of 5. While each bead in the lower deck has a value of 1. Beads are considered counted, when they are moved towards the beam that separates the two decks.

Technique

The abacus tool used in our course is a Japanese abacus called Soroban In Soroban Technology, the centre rod of the Abacus is treated as the units rod i.e. 9th rod (A). It works according to the place value system. (We are using the 17 rod abacus tool)

Towards left all places like tens, hundred etc. will be represented and towards right decimal places will be represented.

Proper finger technique is paramount in achieving proficiency on the abacus. With the Japanese Sorobon, only the left index finger and thumb are used. The lower beads are moved up with the thumb and down with the index finger.

However, certain complex operations require that the index finger move beads up; e.g. adding 3 to 8 (the adding of the three is called Jian Chi Jia Shi which literally means, “subtract 7 add 10”).

With the abacus, constant practice is indispensable, in achieving virtuosity and calculating speed.