Define a period

...

How many working days in year 2009?

Here is the detail of the calculation:

Because 2009 is not a leap year, it has 365 days.

Let's remove 52 saturdays and 52 sundays. It remains 261 days.

Now, let's remove 5 public holidays that do not fall during a weekend and we obtain 256 working days in 2009.

Here is the list of these 5 public holidays:

1. Pesach : Thursday, 9 April, 2009
2. Shvi'i shel Pesach : Wednesday, 15 April, 2009
3. Yom Ha-Atzmaut : Wednesday, 29 April, 2009
4. Rosh Hashanah : Sunday, 20 September, 2009
5. Yom Kippur : Monday, 28 September, 2009

And here are the 4 public holidays falling on a weekend:

1. Shavuot : Friday, 29 May, 2009
2. Rosh Hashanah : Saturday, 19 September, 2009
3. Sukkot : Saturday, 3 October, 2009
4. Shemini Atzeret / Simchat Torah : Saturday, 10 October, 2009