1. Find the code: find the code on the transparent paper of each cigarette, which is usually located on the package or cigarette case.

2. Determine the factory date: When coding, pay attention to the first five digits, which represent the factory date of cigarettes. These figures are expressed in years, months, days or other forms.

Considering the storage time in the warehouse: I know it will take some time for the produced cigarettes to be sold in the warehouse. This time is about 10 days.

4. Calculate the actual production date: delay the factory date by about 10 days to get the approximate actual production date.