How to use abacus correctly?

Generally, an abacus has one bead above and four beads below. The lower bead stands for 1 and the upper bead stands for 5. If 1, dial one bead at the bottom, 2, dial another bead. 4 Just dial four beads, and when it is five, dial down the upper bead and the lower four.

Generally, from the ninth gear to the fifteenth gear, the beam is placed horizontally on the gear, two beads are placed on the beam, each bead counts as five, and five beads are placed under the beam, each bead counts as one. Calculate the beads after positioning, and you can do algorithms such as addition, subtraction, multiplication and division.

Extended data:

The formula of abacus:

1, the formula of addition: addition with or without carry, direct addition of five to ten, breaking of five to ten,

Plus one: one up one, five down four, one to nine into one;

Plus two: two up, two down, five down, three down, and two down by 81%;

Plus three: three against three, three against five against two, three against 71%;

Plus four: four up, four down, five to one, four to sixty-one;

Plus five: five goes up to five, five goes to five and enters one;

Plus six: six to six, six to 41%, six to one to 51%;

Plus seven: seven to seven, seven to three, seven to two to five;

Plus eight: eight goes up to eight, eight goes to two and enters one, and eight goes up to three and enters five;

Plus nine: nine on nine, nine into one, nine on four into five;

2. Subtraction formula: If the demotion does not abdicate, it will be directly reduced by five, and the demotion will be reduced by ten and five.

Minus one: one, four to five, one to nine;

Minus two: two down two, two up three down five, two back to eighteen;

Minus three: three times three, three times two to five, three times one to seven;

Minus four: four times four, four times one to five, four times one to six;

Minus five: five times five, five times one, five times;

Minus six: six drops six, six retreats one to four, and six retreats one to five to one;

Minus seven: seven drops seven, seven drops one to three, and seven drops one to five to two;

Minus eight: eight drops eight, eight times one to two, eight times one to five to three;

Minus nine: nine down nine, nine back to one and one, nine back to one and five to four;

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