In the Jewish calendar there are 354 days but in a leap year there are 383 days.
Just like the familiar western civil/business calendar does, the occasional introduction
of Leap Years adjusts the year to a long-term average of 3651/4 days.
This may sound odd or surprising, but in the Hebrew ritual calendar, different months
can have different lengths. (You may want to recall January-31, February-28, etc.) Also,
some months can be a day longer or shorter in different years.
In general, the months of the Hebrew ritual calendar sync closely to the moon's phases,
so the average of any long series of months will be 29.53 days per month. That's 4 weeks
and 1.53 days on the average.
The Jewish calendar usually consists of twelve lunar months. It keeps in step with the solar year by adding a thirteenth lunar leap-month seven times every nineteen years. The Gregorian calendar, which sticks to the solar year, ignores the lunar months and does not attempt to keep in step with them.
Jewish years have different lengths. Some are as short as 354 days and some are as long as 386 days, so the math has variance.
As I write this, it is September 2011. The Jewish year of 5772 will begin in a few days.
7 days.
An abundant year is an example of a longest possible year in the Jewish calendar, either a common year of 355 days or a leap year of 385 days.
There is currently no Jewish army, that was back in Biblical days.
No, the Jewish year has 365.25 days, just like the Gregorian, but the calendar is calculated differently. The Gregorian calendar is Solar, meaning it's based on the Sun; the Jewish calendar is Lunisolar, meaning its based on the Moon, but periodically corrected to match the Sun. By contrast, the Islamic calendar is Lunar and has only 354 days in a year.
Hanukkah, the Jewish festival of lights, lasts eight days.
29.
It depends on what the date is.
There are 365 days in a year. If it is a leap-year, then there are 366 days.
Jewish days begin at sunset.
Yom Kippur