The problem of calculating the genus of a known year is essentially to find the order of earthly branches of a year. Because the earthly branches cycle every twelve years, as long as there is a known earthly branch order for one year, the genus of any year can be deduced. For example, it is known that 1924 and 1984 are all Jiazi years, so the order of earthly branches of 1936, 1948, 1960 and 1972 is "sub". For example, if we find the zodiac sign of 1965, it is known that 1960 is the year of the rat, and 1965 is five years after 1960, then it is a "snake" five years later from the perspective of "offspring". So the genus 1965 is "year of the snake".

2. It is known that there are three commonly used methods to calculate the actual age: (1) according to the zodiac of the year. For example, 1992 someone is 52 years old. What is the zodiac? 1992 is known as the Year of the Monkey, so people aged 48 and 60 are monkeys. Some people are 52 years old, four years older than 48 years old, and small 8 is 60 years old. Therefore, it can be inferred from the "Shen Monkey" that four are backward or eight are forward, and the conclusion is that they belong to a "dragon". (2) If 1992 you are 20 years old and belong to a "rat", then people who are 12 years old and 24 years older than you also belong to a rat. Some people are 35 years old, three years older than 32 and nine years younger than 44. So, you can start with a "mouse", push back three places or push forward nine places, and the conclusion is that it belongs to a "chicken". (3) Earthly branches based on the year of birth. If someone is 1992 18 years old, what is the zodiac? It is known that 1924, 1936, 1948, 1960, 1972, 1984 are all years of the rat, and it is also known that he was born in1984. 1974 is two years after 1972, so it was only after "mouse" that I realized that "(Yin) tiger" was someone's zodiac sign.

3. The common method to calculate the actual age from the known zodiac and "face" (relative age) is to calculate according to the zodiac of that year. If 1992 is called the Year of the Monkey, how old are the young people who belong to the rat? It is known that the year of the rat is four years later than the year of the monkey, so the young people who belong to the rat are four years younger than the young people who belong to the monkey (24 years old), that is, 20 years old; Another example is a man in his forties who claims to be a dragon. How old is he? It is known that the actual age of people in their forties who belong to the monkey is 48 (1992), and the Year of the Loong is 8 years after the Year of the Monkey or 4 years before the Year of the Monkey, so the dragon is always 4 years older than small 8 who belongs to the monkey, and some people are 40 or 52 years old. One of them can be sure by looking at his face again.