Question

How do you find the day of a particular date without calendar? 

Answer 1

MONTH CODES: 

January: 1
Feb         : 4
march    :4
april      :  0
may      :2
june    : 5
july       :0
august  :3
sept    :6
oct  :      1
november   :4
december   : 6.   

CENTURY CODES:
    
    1500-1599 : 0
 1600-1699    :  6
1700-1799     :  4
1800-1899     :  2
1900-1999     :  0
2000-2099      :6.

DATE CODES:
    
       sat - 0
        sunday - 1
        monday- 2
        tues - 3
        wed - 4
        thur - 5
        fri - 6.



FORMULA :  
    
        DATE+month code+no.of leap years +year+century code.

eg:  4th july 1988 which day?
   
     
       4+5+22    (for leap years you have to divide last 2 digits of year with 4 and you have to write quotient but not in decimal form. you can leave remainder.)+   88    (you have to write last two digits of that year)+0.
       
      = 31. 
now, you have to divide with 7 as weak has 7 days.

you will get remainder 2. so according to day code 2 is monday.