By Honorary Reporter Adriana Castilblanco from Mexico

Photo = Adriana Castilblanco

The abacus is considered the oldest calculating device used by humans but in the 1940s, a Korean man invented an abacus-like counting method using fingers called jisanbeop or chisanbop, a term that literally means "finger calculation."

Created by Pai Sung-jin and modified by his son Hang-young, this system is based on the abacus but uses human hands. By assigning numbers to each finger on both hands, jisanbeop can be used to count from 1-99 as well as solve math problems.

Assigning numbers

A value is assigned to each finger on both hands, as well as a positional notation depending on the hand used. The left hand represents tens and the right ones.

Each finger on the left hand, from the index to the pinky, represents the number 10, while the thumb represents 50. On the right hand, the index, middle, ring and pinky fingers each represent one and the thumb five.

Thus the left hand is used to count 10, 20, 30 and so on and the right one through nine.

How to count and solve problems

Using this method, always start with both hands in the air, and every time a new number is added to the formula, each finger being counted has to be pressed on the surface underneath to show its use in the problem. One must also start counting with the index finger, followed by the middle, ring and pinky fingers and ending with the thumb. Then start with the index finger again.

Under this method, the number 12 is expressed by pressing the index finger on the left hand (10) and the index and middle fingers of the right (1+1).

To express a bigger number like 73, press the left thumb (50) and the left index and middle fingers (10+10) as well as the index, middle and ring fingers on the right hand (1+1+1).

This method is useful for improving one's math ability, as well as coordination when trying to think about expressing numbers with the hands. Jisanbeop is more limited than an abacus because counting only up to 99 is possible, but this system is helpful for children just learning to add and subtract or those seeking to boost their math skills or simply learn something new.

enny0611@korea.kr

*This article is written by a Korea.net Honorary Reporter. Our group of Honorary Reporters are from all around the world, and they share with Korea.net their love and passion for all things Korean.