The concentration of brine is equal to the salt content divided by the salt content multiplied by 100%. Salt water often refers to seawater or common salt solution. The calculation formula of salt water concentration in primary schools is: salt water concentration is equal to salt content divided by salt water quality multiplied by 100%. The content of dissolved salt in seawater is 35,000 mg per liter, of which chloride is 20,000 mg per liter.