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How many working days in year 1980?

Here is the detail of the calculation:

Because 1980 is a leap year, it has 366 days.

Let's remove 52 saturdays and 52 sundays. It remains 262 days.

Now, let's remove 7 public holidays that do not fall during a weekend and we obtain 255 working days in 1980.

Here is the list of these 7 public holidays:

1. New Year's Day : вторник, 1 январь, 1980
2. Good Friday : пятница, 4 апрель, 1980
3. Easter Monday : понедельник, 7 апрель, 1980
4. May Day : четверг, 1 май, 1980
5. Ascension Day : четверг, 15 май, 1980
6. Christmas Day : четверг, 25 декабрь, 1980
7. St Stephen's Day : пятница, 26 декабрь, 1980

And here are the 6 public holidays falling on a weekend:

1. Epiphany : воскресенье, 6 январь, 1980
2. Easter Sunday : воскресенье, 6 апрель, 1980
3. Whit Sunday : воскресенье, 25 май, 1980
4. Midsummer Day : суббота, 21 июнь, 1980
5. All Saints' Day : суббота, 1 ноябрь, 1980
6. Independence Day : суббота, 6 декабрь, 1980