Gregorian calendar is very regular. The number of days in a normal year is 1, and the number of days in February and March is 3 1, 28, 3 1, totaling 90 days.

90= 12x7+6

So 202 1 year (including other normal years) is 12 full week and 6 days.

Extended data

4_6_9_ 1 1 refers to 30 days of abortion,1_ 3 _ 5 _ 7 _ 8 _10 _/2 refers to 3 months1day, and the average year is 28 days.

The average solar calendar year is divided into twelve months, the first month is 3 1 day, the second month is 30 days, and the second month is 28 days. The average calendar month is approximately equal to the average length of Wang Shuo's month of 29.5306 days. The size of the months in the solar calendar is regular. Before July, a single month was a big month and two months was a small month. After August, two months are big months and a single month is small, so 1 month, March, May, July, August,1month,1February are big months, and April, June, September,1/kloc.

In the julian calendar implemented by Roman dictator Julius Caesar in BC 1, it was originally an alternate month, in which August was originally designated as a small month, because the later dictator Octavian was born in this month, the Senate changed this month to his title "Augustus", and took a day out of February to make up for it, turning it into a big month and rescheduling the following months.