In Fujian Xiamen, if the social security base is 17,500 yuan, the tax deduction is calculated as follows:

1. Determine the applicable tax rate:

• First, calculate the taxable income. The individual income tax threshold in China is 5,000 yuan.

• Social security deductions:

• Pension insurance: The individual contribution rate is usually 8% of the salary. So for a social security base of 17,500 yuan, the pension insurance deduction is ​
  ×8%=
  yuan.

• Medical insurance: The individual contribution rate is about 2%. So the medical insurance deduction is ​
  ×2%=
  yuan.

• Unemployment insurance: The individual contribution rate is around 0.5% (in some cases, it may vary slightly in different regions, but generally within 0.2% - 1%). Here, calculated at 0.5%, the unemployment insurance deduction is ​
  ×0.5%=87.5
  yuan.

• The total social security deductions are ​
  ++87.5=1837.5
  yuan.

• The taxable income = monthly income - 5000 - social security deductions. Substituting the values, the taxable income is ​
  −−1837.5=10662.5
  yuan.

• According to the individual income tax rate table, for a taxable income range of 8000 - 17000 yuan, the applicable tax rate is 10%, and the quick - calculation deduction is 2520 yuan.

2. Calculate the individual income tax:

• The formula for calculating individual income tax is: Tax payable = taxable income × applicable tax rate - quick - calculation deduction.

• Substituting the values, the tax payable is ​
  10662.5×10%−

• First, ​
  10662.5×10%=1066.25
  yuan.

• Then, ​
  1066.25−=−1453.75
  yuan. But in fact, since the quick - calculation deduction is wrongly applied in this case (the quick - calculation deduction is designed for cumulative tax calculation in a more complex scenario), we should calculate it step - by - step.

• The part of the taxable income within 3000 yuan is taxed at 3%: ​
  ×3%=
  yuan.

• The part of the taxable income from 3000 - 12000 yuan is taxed at 10%. The amount in this part is ​
  10662.5−=7662.5
  yuan, and the tax for this part is ​
  7662.5×10%=766.25
  yuan.

• The total tax payable is ​
  +766.25=856.25
  yuan.

In conclusion, when the social security base in Xiamen, Fujian is 17,500 yuan, after calculating the social security deductions and applying the individual income tax rate, the individual income tax payable is approximately 856.25 yuan. However, this calculation does not consider special additional deductions. If there are special additional deductions such as housing loan interest, children's education, etc., the taxable income will be further reduced, and the tax payable will also change accordingly.