One degree (Kala) of Moon is said to be a date. Similarly 30 dates are formed by the combination of Shukla and Krishna Paksha. There are 2 Karana in one date, according to which, there should be 60 Karna in a moon month
Gar Karana comes in the category of Char Karana. Hindu Panchang has 5 parts : date, day, Nakshatra, Yoga and Karana. There are only 11 Karana. The 1st seven Karana keep repeating whereas, the left over four Karana