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.

The 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
step 6.