How many working days in year 2109?
Here is the detail of the calculation:
Because 2109 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 2109.
 Here is the list of these 5 public holidays: 
 
 1. New Year's Day : 2109年1月1日星期二 
2. Good Friday : 2109年4月19日星期五 
3. Labour Day : 2109年5月1日星期三 
4. National Day : 2109年8月9日星期五 
5. Christmas Day : 2109年12月25日星期三