How did birthdays become gossip fortune telling?

Birthdates calculates the upper divination according to the sum of years, months and days divided by the remainder of 8, and then calculates the lower divination according to the sum of years, months and days divided by the remainder of 8. In this way, the upper divination and the lower divination are combined into one, becoming one of the sixty-four hexagrams, which is the process of divination device. Then add up the remainder of the year, month and day divided by 6 to calculate the variation, and then comprehensively analyze and judge other years, months and days, other hexagrams and six relatives based on this variation.