How to calculate the economic compensation for employees when Nikon closes Wuxi factory?

The unit shall pay economic compensation according to the working years of the laborer in the unit, and compensate one month's salary for each full year, half a month's salary for less than half a year, and one month's salary for less than half a year. For example, 3 years and less than 3.5 years is 3.5 months' salary, and 3.5 years and less than 4 years is 4 months' salary. At the same time, the unit shall notify the workers in writing 30 days in advance, or pay an extra month's salary. The base of economic compensation is calculated according to the average monthly salary of the laborer 12 months (less than 12 months is calculated according to the actual number of months) before the dissolution or termination of the labor contract.