The Chinese abacus, built of wood and beads, was invented during the 11th century; however, the inventor remains unknown. The earliest written record of the abacus dates back to 14th century AD. The Mandarin term for the Chinese abacus is “suan pan”, which means “calculating plate”. This hand held and portable device is often referred to as the “first computer”. However, unlike modern day calculators, the abacus doesn’t actually do the computing. It requires manual manipulation; thus, accuracy depends heavily on the user. In the past, people skilled in performing abacus computations could do calculations as quickly as those using simple electronic calculators. Counting in base 10, the abacus can be used to perform multiplication, division, addition, subtraction, square root, and cube root calculations.
Typically, the abacus is approximately 20 cm tall with varying widths and at least seven rods. The number of rods determines the computation capacity. Abacuses are normally constructed of either hardwood and/or metal. A horizontal separator beam divides the abacus into two decks, upper and lower. The upper deck is referred to as “heaven”, and the lower deck is referred to as “earth”. In the upper deck, there are two beads, also referred to as “heaven beads”, on each rod. In the lower deck, there are five beads, also referred to as “earth beads” on each rod.
General How to Use
The abacus must be placed on a flat surface when in use. The beads are manipulated typically with the index finger and the thumb of one hand. Beads are counted by moving them up with the thumb or down with the index finger towards the horizontal separator beam. Moving towards the horizontal separator beam adds value, while moving away from the horizontal separator beam takes away value. The abacus resets to 0 when the beads are pushed back to their original positions.
“Heaven beads” carry a value of 5 in their column, while “earth beads” carry a value of 1 in their column. This structure is used for both decimal and hexadecimal computation. Because the abacus works on the principle of place-value notation, the location of the bead determines its value. The places of the columns are similar to the Arabic numeric system. The rightmost column represents the ones place. The column next to that represents the tens place, then the hundredths place, then the thousandths place, etc.
Chinese Abacus Today
Today, the abacus is still used in Asia in children’s classrooms to teach multiplication and simple mathematics. They have speed calculation competitions for children as well. Blind children can be taught to perform calculations using the abacus. In some cases, the elderly actually prefer the abacus over today’s electronic devices. It is not uncommon to see Chinese store owners and/or street vendors using the abacus to help with billing. Of course, with today’s technology, those using the abacus can’t beat those using electronic calculators when it comes to calculations.