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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 14 public holidays that do not fall during a weekend and we obtain 247 working days in 1970.

Here is the list of these 14 public holidays:

1. New Year's Day : четверг, 1 январь, 1970
2. Coming of Age Day : понедельник, 12 январь, 1970
3. Foundation Day : среда, 11 февраль, 1970
4. Vernal Equinox Day : пятница, 20 март, 1970
5. Shōwa Day : среда, 29 апрель, 1970
6. Greenery Day : понедельник, 4 май, 1970
7. Children's Day : вторник, 5 май, 1970
8. Marine Day : понедельник, 20 июль, 1970
9. Respect-for-Aged Day : понедельник, 21 сентябрь, 1970
10. Autumnal Equinox Day : среда, 23 сентябрь, 1970
11. Health and Sports Day : понедельник, 12 октябрь, 1970
12. Culture Day : вторник, 3 ноябрь, 1970
13. Labor Thanksgiving Day : понедельник, 23 ноябрь, 1970
14. Emperor's Birthday : среда, 23 декабрь, 1970

And here is the public holiday falling on a weekend:

1. Constitution Memorial Day : воскресенье, 3 май, 1970