《晋书·志·第七章》
以章岁十九乘以天正朔小余，除以会数四十七，所得商数为大分；余数为小分。
以章岁乘朔小余，满会数为大分；不尽，小分。
Multiply the base value, nineteen, by the difference between the first day of the correct lunar month and the first day of the correct solar month, and divide the product by the interrelation number forty-seven. The quotient is the large fraction, while the remainder is the small fraction.