Question 23
A date is called a lucky date if the sum of the digits when it is written in the form MMDDYY is 13. The date January 9, 2021 when written as 010921 is a lucky date because the sum of the digits is 13 and February 8, 2021, when written as 020821 is a lucky date as well because the sum of the digits is 13. However, March 8, 2021 is not a lucky date because the sum of the digits is 14. How many lucky dates are there in 2021?