Define a period

...

How many working days in year 1981?

Here is the detail of the calculation:

Because 1981 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 1981.

Here is the list of these 8 public holidays:

1. New Year's Day : Thursday, 1 January, 1981
2. Maundy Thursday : Thursday, 16 April, 1981
3. Good Friday : Friday, 17 April, 1981
4. Easter Monday : Monday, 20 April, 1981
5. Labour Day : Friday, 1 May, 1981
6. Ascension Day : Thursday, 28 May, 1981
7. Whit Monday : Monday, 8 June, 1981
8. Christmas Day : Friday, 25 December, 1981

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

1. Easter Sunday : Sunday, 19 April, 1981
2. Constitution Day : Sunday, 17 May, 1981
3. Pentecost : Sunday, 7 June, 1981
4. St Stephen's Day : Saturday, 26 December, 1981