Easter formula
March 23rd, 2005
Scanning the Excel boards for a formula for Easter that is easily ported to Openoffice Calc.
=FLOOR(”5/” & DAY(MINUTE(B5 / 38) / 2 + 56) & “/” & B5; 7) - 34 + 1
where B5 is the year we wish to find the date on which Easter (Sunday) falls.
This generates American date format MM/DD/YYYY and I believe it is valid to 2075 - which is long enough for me!
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OpenOffice Calc Tips
Date & Time : Calculating Dates of Holidays
October 4th, 2004
This particular exercise in developing formulas for each of the major US holidays is a good way to develop expertise in OOo Calc date manipulation.
US holidays follow simple guidelines for the dates on which they fall. Some holidays fall on specific dates , such as New year’s day on January 1st and independence day on July 4th. Other holidays fall on specific days within the month. For example, Memorial Day is the last Monday in May and Thanksgiving Day is the fourth Thursday in November.
The OOo Calc functions that will feature prominently in this exercise are
DATE(year; month; day) Returns formatted date corresponding to specified year, month, and day values.
WEEKDAY(dateValue; type) Returns a decimal value corresponding to the day of the week for the input date.
Before we tackle the US holidays problem, let us become more familar with the above functions and how they are used in OOo Calc formulas.
The DATE function allows us to define and manipulate a dates components - year, month, and day - independently. We have already seen this in an earlier tip
The WEEKDAY function returns a decimal value between 1 & 7 corresponding to the day of the week for the specified date. By invoking the TEXT with the appropriate formmating, we can convert the output of the WEEKDAY function to something more meaningful. In the example below, both formats are shown. The last two formulas show one approach to determining the first day-of-week after a specified date.
The table below generates the 10 major US holidays for a specified year - in cell C2
New Year’s Day =DATE(C2;1;1)
Martin Luther King Jr. DayThis is the third Monday in January. =DATE(C2;1;IF(2<WEEKDAY(DATE(C2;1;1));10-WEEKDAY(DATE(C2;1;1));3-WEEKDAY(DATE(C2;1;1)))+14)
President’s Day This is the third Monday in February.
=DATE(C2;2;IF(2<WEEKDAY(DATE(C2;2;1));10-WEEKDAY(DATE(C2;2;1));3-WEEKDAY(DATE(C2;2;1)))+14)
Memorial Day The last Monday in May, we subract 7 days from the first Monday in June. =DATE(C2;6;IF(2<WEEKDAY(DATE(C2;6;1));10-WEEKDAY(DATE(C2;6;1));3-WEEKDAY(DATE(C2;6;1)))-7)
I leave the rest for you as an exercise!
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Financial Functions 3 : Complex Accumulation
October 7th, 2004
In this example, we consider a more complex accumulation - wherein we are making regular payments as well as earning interest on our initial investment.
Here, we define names for the cells containing the main variables - so that the formulas are more readable.
The purpose of the month-by-month breakdown of the account also serves to confirm the accuracy of our original formula.
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