How is the month calculated?

1, 3, 5, 7, 8, 10, 12 are big months, with 3 1 day; February in a normal year has 28 days and leap year has 29 days. 4, 6, 9, 1 1 all miscarried for 30 days. This is the Gregorian calendar, and the size of the lunar month is not fixed. It depends on the Gregorian calendar. As for counting fingers, I learned it in primary school. The specific method is as follows: make a fist with your left hand, counting from the index finger joint, the protrusions and depressions, counting to the last one, counting from the index finger, and counting to 12. The big moon is prominent, and the small moon is depressed, except in February.