How to play the abacus:

When starting the calculation, all the beads must be returned to the lower row. The beads in the upper row represent the number 5, and each bead in the lower row represents the number 1.

Specify a fixed digit value in each column, so the first column from the right should be the ones digit (1-9), the second column should be the tens digit (10-99), and the third column should be the hundreds. bits (100-999) and so on.

When counting, dial up the beads. 1 is represented by dialing up one bead in the row below the first column on the right, 2 is represented by dialing up two beads, and so on.

The abacus formula (nine-return formula):

One return (divided by 1): every one enters one, every two enters two, every three enters three, every four enters four , every five goes into five, every six goes into six, every seven goes into seven, every eight goes into eight, every nine goes into nine.

Two returns (divided by 2): every two goes into one, every four goes into two, every six goes into three, every eight goes into four, and two and one add to make five.

Three returns (divided by 3): every three will make one, every six will make two, every nine will make three, three, one, three will leave one, and three, two, six will leave two.

Four returns (divided by 4): every four makes one, every eight makes two, four and two add to make five, four and one and two make two, four and three and seven make two.

Five returns (divided by 5): when five is added, one is added, five times is doubled to make two, five to two times is made to four, five or three times is made to six, and five or four times is made to eight.

Liu Gui (divided by 6): every six adds one, every twelve adds two, six three adds five, six one adds four, six two three leaves two, six four six leaves four, Sixty-five-eight and two more.

Seven returns (divided by 7): every seven adds one, every fourteen adds two, seven plus three plus seven, seven two plus six, seven three four leaves two, seven four five leaves five, Seventy-five-seven means more than one, and seven-sixty-eight means more than four.

Eight returns (divided by 8): Every eight adds one, eighty-four adds five, eighty-one adds two, eighty-two adds four, eighty-three adds six, and eighty-five and six leave two. Eighty-sixty-seven is more than four, eighty-seven is more than six.

Nine returns (divided by 9): every nine adds one, nine one adds one, nine two adds two, nine three adds three, nine four adds four, nine five adds five, Add six to ninety-six, seven to ninety-seven, and eight to ninety-eight.

Main types of abacus

It is worth noting that the term abacus does not specifically refer to Chinese abacus. Judging from the existing literature, many ancient civilizations had their own calculation tools similar to abacus. All kinds of abacus from ancient and modern times at home and abroad can be roughly divided into three categories: sand table type, abacus board type, and bead abacus type.

A sand table is a flat surface such as a desktop or a stone slab, covered with fine sand. People use wooden sticks to write, draw and calculate on the fine sand. Later, instead of spreading sand, a number of parallel lines were carved on the board, and small stones (called "calculators") were placed on it to record numbers and calculations. This is the abacus board. A 1-meter-long marble abacus discovered in Salamis, Greece in the mid-19th century is an ancient Greek abacus and is now in the Athens Museum.

The abacus board has always been an important calculation tool in the European Middle Ages, but the form varies greatly. The lines are straight or horizontal, the counters are round or flat, and sometimes they are conical (similar to checkers). There are also numbers on it. Pearl abacus refers to Chinese abacus, Japanese abacus and Russian abacus. The Japanese abacus is called "Shilu Pan". It is different from the Chinese abacus in that the longitudinal section of the abacus is not oblate but rhombus, with smaller size and more steps. The Russian abacus has a number of curved wooden bars set horizontally in a wooden frame, each with 10 abacus beads. Among the various ancient abacus in the world, the Chinese abacus is the most advanced abacus tool.