Lunar calendar average length of the synodic month is days. Thus it is convenient if months generally alternate between 29 and 30 days (sometimes termed respectively “"hollow"” and “"full"”). The distribution of "hollow" and "full" months can be determined using continued fractions, and examining successive approximations for the length of the month in terms of fractions of a day. In the list below, after the number of days listed in the numerator, an integer number of months as listed in the denominator have been completed: These fractions can be used to construct a lunar calendar, or in combination with a solar calendar
Adhik Maas "adhika"; "maal", "māla"; "maas", "maasa", "mās", "māsa", "mas", "mass". This is the thirteenth month of the lunar calendar. Adhik Maas adopts the name of the month that follows. Purushottam Maas is considered inauspicious and no activities like weddings or moving into a new house are conducted. It is a time for prayer, fasting, charity, and self-improvement. According to "Vasishtha Siddhantha" (the treatise of Vasishtha), Purushottam Maas or the extra lunar month occurs after every 32 months, 16 days and 8 "ghati". (A "ghati" is th of a sidereal day, approximately 24 minutes, so 8 "ghati" is about 3 hours.) In