In Anhui Wuhu, if the social security base is 5600 yuan, it approximately corresponds to the eighth grade among the nine-grade setting for flexible - employment pension insurance. Here's the detailed analysis:

1. Grade setting basis: The social security payment base in Wuhu is determined according to a certain percentage of the average monthly wage of all - employees in urban units in the previous year in the whole province. For flexible - employment pension insurance, the monthly payment base is divided into nine grades, which are respectively 60%, 70%, 80%, 90%, 100%, 120%, 150%, 200%, and 300% of the average social wage in the previous year.

2. Calculation of corresponding grade: Given that the average monthly wage of all - employees in urban units in the whole province in 2022 was 6698.08 yuan. Calculate the payment base of each grade:

• The first grade (60%): ​
  6698.08×60%=4018.85
  yuan.

• The second grade (70%): ​
  6698.08×70%=4688.66
  yuan.

• The third grade (80%): ​
  6698.08×80%=5358.46
  yuan.

• The fourth grade (90%): ​
  6698.08×90%=6028.27
  yuan.

• The fifth grade (100%): ​
  6698.08×100%=6698.08
  yuan.

• The sixth grade (120%): ​
  6698.08×120%=8037.70
  yuan.

• The seventh grade (150%): ​
  6698.08×150%=10047.12
  yuan.

• The eighth grade (200%): ​
  6698.08×200%=13396.16
  yuan.

• The ninth grade (300%): ​
  6698.08×300%=20094.24
  yuan.

• Since 5600 yuan is between 5358.46 yuan (80% grade) and 6028.27 yuan (90% grade), and is closer to the 80% grade, it can be approximately considered as corresponding to the eighth grade among the nine - grade setting for flexible - employment pension insurance.

It should be noted that the above is mainly analyzed from the perspective of flexible - employment pension insurance. For employee social security in enterprises, the payment base is determined according to the employee's own monthly average wage in the previous year. If the wage is between the upper and lower limits of the payment base, it is paid according to the actual wage. The upper limit of the social security payment base in Wuhu in 2023 is 20094 yuan, and the lower limit is 4019 yuan.