Abacus is an auxiliary tool for manual operation and calculation. It originated in China and has a history of more than 2,600 years. This is an important invention in ancient China. Before Arabic numerals appeared, abacus was a widely used computing tool in the world. Abacus formulas include addition formula, subtraction formula, multiplication formula and division formula.
First, the abacus formula jingle:
1, one up one, two up two, three up three, four up four, five up five, six up six, seven up seven, eight up eight, nine up nine.
2, one drops five to four (4+ 1), two drops five to three (3+2, 4+2), three drops five to two (2+3, 3+3, 4+3) and four drops five to one (1+4, 2+4, 3).
3. One to nine into one (9+ 1), two to eight into one (8,9+2), three to seven into one (7,8,9, +3), four to six into one (6,7,8,9+4), five to five into one (5,6,6).
4. Six on one to five into one (5, 6, 7, 8+6), seven on two to five into one (5, 6, 7+7), eight on three to five into one (5, 6+8) and nine on four to five into one (5+9).
Second, Zhu Shijie (1299), a great mathematician in the Yuan Dynasty, further promoted the book "Arithmetic Enlightenment" to the following fifteen sentences:
One begging, every 625; (116 = 0.0625) Second, abdicate125; (2/ 16=0. 125) three solutions, 1875 records; (3/ 16=0. 1875) four demands, changed to 25; (4/ 16=0.25) five, three one two five is; (5/ 16=0.3 125) Six seeking, bivalent 375; (6/ 16=0.375) Seven requests, four three seven five placements; (7/ 16=0.4375)
Eight seeking, turning into five; (8/ 16=0.5) Jiuqiu, 5625; (9/ 16=0.5625) Ten, 625; ( 10/ 16 = 0.625) 1 1, 6875; (1116 = 0.6875)12,75; ( 12/ 16 = 0.75) 13, 8 125; ( 13/ 16 = 0.8 125) 14, 875; ( 14/ 16 = 0.875) 15, 9375; ( 15/ 16=0.9375)
Three, abacus abacus formula table
Business withdrawal formula: nothing more than withdrawal, nothing more than withdrawal, two, three, four, five, six, seven, eight and nine.
The formula of quotient nine * * 9 sentences: See no score 9 1, no score 2 92, no score 3 93, no score 4 94, no score 5 95, no score 6 96, no score 7 97, no score 8 98 and no score 9 99.