Seven-character is the most popular number in the world. For example, all over the world, it is mandatory to have seven days a week, from Monday to Saturday and Sunday. Even those who study and practice Buddhism like to spend seven days, reciting Buddha for seven days, repenting to Buddha for seven days, or 372 1 day, chanting sutras for as few as seven times, 2 1 time for as many as 7749 times.

The origin of "Xiao Jiujiu" The multiplication formula of multiplication table has existed for a long time in ancient China. "The weight of the pipe" says: "The filter drama makes six holes to meet Yin and Yang, so that the number of ninety-nine is in line with heaven." "Han Shi Zhuan" cloud; "Qi Huangong gave a banquet in the imperial court, and others will come. In 1999, there will be people watching." The ancient multiplication formula is from top to bottom, from "998 1" to "one to one", and the order is opposite to the remainder. The ancients used the word "99" at the beginning of multiplication formula as the name of this formula, so it was called 99 multiplication table. The 99-99 multiplication melody is also often called "Little 99". The formula of "occupation" that students are learning now is

From "one to one" to "998 1", but in ancient times, it was the other way around, from "998 1" to "one to one". Because the first two words of the formula are "99", people call it "99" for short. It was only in the 13 and 14 centuries that it turned into the present situation. China used the "99 formula" earlier. Sentences such as "3927", "684 18", "483 12" and "6636" can be found in books such as Xunzi, Guanzi, Huainanzi and Warring States Policy. It can be seen that as early as the Spring and Autumn Period and the Warring States Period, 99 multiplication songs became popular. Nowadays, people generally describe those who are good at calculating, calculating and planning as having a "career" in mind. Jiujiubiao, also known as Jiujiuge and Jiuyinge, is the basic calculation rule in multiplication, division, square root and other operations in ancient China. It has been used for more than two thousand years. Now primary school students and some school-age children can recite it. But Europe didn't know this simple multiplication table until the beginning of 13 century. The ancient western civilizations Greece and Babylon also invented the multiplication table, but it is more complicated than the 999 table. There are more than 1700 Greek multiplication tables invented by Babylon, and they are not complete enough. Because they worked hard to calculate multiplication and division before 13 century, people who can divide large numbers will be considered as experts in mathematics. /kloc-At the beginning of the third century, the eastern calculation method was introduced to Europe through Arabs, and Europeans discovered its convenience, so they learned this new method. At that time, the topic of multiplying two numbers by a new method was the textbook of the university at that time.