Day FindingDate: 07/17/97 at 12:58:15 From: Roshan Anthonypillai Subject: Day finding What is the formula to find the day of the week, given the date, month, and year? Thanks. Roshan Date: 08/16/97 at 15:20:53 From: Doctor Terrel Subject: Re: Day finding Hi Roshan, I found something that might help you - from Australia! Isn't that neat? Here it is... Calculating the Day of the Week For Any Year Here is a standard method suitable for mentally computing the day of the week from the date: 1. Take the last two digits of the year. 2. Divide by 4, discarding any fraction (remainder). 3. Add the day of the month. 4. Add the month's key value: JFM AMJ JAS OND 144 025 036 146 [You should take that last line to mean: jan = 1, feb = 4, mar = 4, etc.] 5. Subtract 1 for January or February of a leap year. 6. For a Gregorian date, add 0 for 1900's, 6 for 2000's, 4 for 1700's, 2 for 1800's; for other years, add or subtract multiples of 400. 7. For a Julian date, add 1 for 1700's, and 1 for every additional century you go back. 8. Add the last two digits of the year. 9. Divide by 7 and take the remainder. Now 1 is Sunday, the first day of the week, 2 is Monday, and so on. Calculating the Day of the Week for the Current Year A good mnemonic rule to help on the computation of the day of the week is as follows. In any given year the following days come on the same day of the week: (Note to U.S. citizens - in Australia we use day/month instead of month/day, so 4/7 is July 4.) 4/4 6/6 8/8 10/10 12/12 To remember the next four, remember that I work from 9-5 at a 7-11 so 9/5 5/9 7/11 11/7 and the last day of Feb. In 1996, these dates all fall on a Thursday. To find the day that the 4th of July falls on, for example, use the fact that 11/7 is a Thursday, and hence the 4/7 is also. Taken from: http://www.lib.ox.ac.uk/internet/news/faq/archive/sci-math-faq.dayweek.html -Doctor Terrel, The Math Forum Check out our web site! http://mathforum.org/dr.math/ |
Search the Dr. Math Library: |
[Privacy Policy] [Terms of Use]
Ask Dr. Math^{TM}
© 1994- The Math Forum at NCTM. All rights reserved.
http://mathforum.org/dr.math/