65. The total solar months expired . The Adimath, by Thandeikta, is the quotient of
and the remainder is Adimath thetha, The ratio 28 : 911 is the difference between unity and 939 : 911, which is an approximation to 13,358,334 : 12,960,000, the Surya Siddhanta ratio of the length of a mean solar month to the length of a mean lunar month (para. 34). is a correction to obtain a closer approximation. The constant 690 is the adimath thetha at the end of the 1100th year of Poppasaw's era.
66. Makaranta not only omits the correction , but takes a slightly rougher approximation of the Surya Siddhanta ratio, viz., 940 : 912, because this ratio can be reduced to lower terms, namely 235 : 228. This is the ratio of the Metonic cycle; nineteen years contain 235 lunar months, 228 solar months.
67. Total lunar months (L.M.) . , that is to midnight preceding the day . Kaya, by Thandeikta, is the quotient of
and the remainder is awaman. . The day of the week is the remainder of .
68. The kyammat of the whole period is . Divide this by 292207. The quotient is Ratha, and the remainder is kyammat-pon, or the kyammat of the fraction of a year elapsed during the current solar year. Divide kyammat-pon by 800. The quotient is Thokdadein, and the remainder is Ata kyammat.
69. Makaranta, by using the Metonic cycle, takes a different method of arriving at the total didi, and at the same time ascertains the intercalary months and days. The watat years are first found by the Metonic cycle, and then the yet-bo for midnight preceding the Labyi of Second Wazo of each watat year are calculated, as follows.
70. Divide the year by 19. The quotient is the expired cycles. If the remainder is 2, 5, 7, 10, 13, 15 or 18 there is an intercalary month. These alone are the years with which we are concerned at present.
71. The expired cycles multiplied by 7050 (235 × 30) = the total didi of the completed cycles, ending on the Lagwè of Tabaung. To find the didi of the remaining years and fraction, first multiply these years by 12. Add 4 for the
