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How many working days in year 1987?

Here is the detail of the calculation:

Because 1987 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 1987.

Here is the list of these 5 public holidays:

1. New Year's Day : четверг, 1 январь, 1987
2. Good Friday : пятница, 17 апрель, 1987
3. Labour Day : пятница, 1 май, 1987
4. National Day : понедельник, 10 август, 1987
5. Christmas Day : пятница, 25 декабрь, 1987

And here is the public holiday falling on a weekend:

1. National Day : воскресенье, 9 август, 1987