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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 10 public holidays that do not fall during a weekend and we obtain 252 working days in 1980.

Here is the list of these 10 public holidays:

1. New Year's Day : вторник, январь 1, 1980
2. Martin Luther King Day : понедельник, январь 21, 1980
3. Washington's Birthday : понедельник, февраль 18, 1980
4. Memorial Day : понедельник, май 26, 1980
5. Independence Day : пятница, июль 4, 1980
6. Labor Day : понедельник, сентябрь 1, 1980
7. Columbus Day : понедельник, октябрь 13, 1980
8. Veterans Day : вторник, ноябрь 11, 1980
9. Thanksgiving : четверг, ноябрь 27, 1980
10. Christmas : четверг, декабрь 25, 1980