The formula of primary school tax payment is: tax payable = (total income-tax-free part) × tax rate; Total income = taxable rate+tax-free part; Tax rate = taxable ÷ (total income-tax-free part).

Tax rate: it is the proportion or amount of tax levied on the object of taxation. Tax rate is the measure of calculating tax amount and an important symbol of measuring tax burden. The current tax rates in China mainly include proportional tax rate, excessive progressive tax rate, excessive progressive tax rate and fixed tax rate. The object of taxation is also called the object of taxation and the object of taxation, which refers to the things that are taxed according to the tax law. It is the object or subject matter that the rights and obligations of taxpayers point to, and it is an important symbol to distinguish one tax type from another.