According to the Book of Changes, people in ancient China also "ruled the country by knots", that is, tied a knot on a rope to record events. Later, it was changed to "book deed", that is, it was carved on bamboo or wood with a knife, and a pen represented "one". Today, we in China often use the word "positive" to count. Each stroke represents "one". Of course, the word "positive" also contains the meaning of "five into one"