• What the day of week falls on what date: If you want to calculate the day which is in past then you have to follow a simple procedure which is as if you want to know the day on February 24, 2014 now you are having the data that February is the 2^nd month so its code is 2 and 24 has three 7 so 24-21=3 next is year 2014 the nearest leap year for 2014 is 2012 which is 1 and 2013 is 2 so 2014 is 3 by adding 2+3+3=8 and by subtracting 7 from 8 we have 1 which is Monday.

via lifehacker