Define a period

...

How many working days in year 1970?

Here is the detail of the calculation:

Because 1970 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 8 public holidays that do not fall during a weekend and we obtain 253 working days in 1970.

Here is the list of these 8 public holidays:

1. Nieuwjaarsdag : Thursday, 1 January, 1970
2. Paasmaandag : Monday, 30 March, 1970
3. Dag van de Arbeid : Friday, 1 May, 1970
4. Hemelvaartsdag : Thursday, 7 May, 1970
5. Pinkstermaandag : Monday, 18 May, 1970
6. Nationale Feestdag : Tuesday, 21 July, 1970
7. Wapenstilstand : Wednesday, 11 November, 1970
8. Kerstmis : Friday, 25 December, 1970

And here are the 2 public holidays falling on a weekend:

1. Onze-Lieve-Vrouw Hemelvaart : Saturday, 15 August, 1970
2. Allerheiligen : Sunday, 1 November, 1970