One of the first
recorded mathematical algorithms was developed by Eratosthenes
(about 230 BC) for finding prime numbers.
Our present calendar
is the Gregorian calendar, named for Pope Gregory XIII
in 1582. Great Britain adopted the Gregorian
calendar in 1752 and forced its use in the American colonies.
In 1923, Greece also adopted the Gregorian calendar. Since
then, it has become the standard calendar for nearly all
the countries in the world.
Although Thanksgiving day is usually observed
on the fourth Thursday in
November, its actual date in
any year must be decided by proclamation
of the sitting president of the United States.
first man to walk on the moon, Neil Armstrong, landed
there on a Sunday, July 20, 1969.
When developing software programs, computer
scientists often use flowcharts
to organize their work.
To change the flowchart
to handle years before 1900, add 2 to the sum
in step 6. For years from 1753 to 1800, add
4 to the sum in