According to the mathematical algorithm, only chicken and mouse are compound pairs in the 12 zodiac. The year of chicken is 1945, 1957, 1969, 198 1, 1993, 2005, 20 17, 22. The years of rats are 1948, 1960, 1972, 1984, 1996, 2008, 2020, 2032, all multiples of 4 and 5, so they are also compound pairs.