What is the difference between Gregorian calendar and Hebrew calendar?
The Gregorian calendar and Hebrew calendar are two different systems used for tracking dates and times. Here are some of the key differences between them:

Origin and history: The Gregorian calendar was introduced by Pope Gregory XIII in 1582 as a reform of the Julian calendar, which had been used in Europe since ancient times. The Hebrew calendar, on the other hand, has been in use by Jews for over 3,000 years and is based on the lunar cycle.

Length of the year: The Gregorian calendar is a solar calendar and has a year length of 365 days (with an extra day added in leap years), while the Hebrew calendar is a lunisolar calendar with a year length of either 12 or 13 lunar months, which averages to about 354 days.

Leap years: The Gregorian calendar has a leap year every 4 years, except for years divisible by 100 but not by 400. The Hebrew calendar has a leap year 7 times in a 19-year cycle, in which the third, sixth, eighth, eleventh, fourteenth, seventeenth, and nineteenth years are leap years.

Naming of months: The Gregorian calendar has 12 named months, with January as the first month. The Hebrew calendar has 12 or 13 named months, with Tishrei as the first month and Adar as the last month in a regular year, and Adar I and Adar II in a leap year.

Holidays: The Gregorian calendar is used as the civil calendar in many countries, and its holidays are based on Christian and secular traditions. The Hebrew calendar is used primarily for Jewish religious purposes and has its own set of holidays and observances, such as Rosh Hashanah and Passover.

Overall, the Gregorian calendar is a standard calendar used by much of the world for civil and commercial purposes, while the Hebrew calendar is primarily used for religious and cultural purposes by the Jewish community.