According to the price, the contract can be divided into open contract and closed contract  The opening price refers to the price that can only be determined through calculation according to a certain pricing method, and the closed price refers to the price that has been determined at the time of the conclusion of the contract
A sale contract without a fixed price is an open contract
When Mr. Fang and his wife divorced, they agreed that the daughter would be raised by the woman, and Mr. Fang would pay the woman a monthly maintenance fee of 2000 yuan until the child reached adulthood. If the child has additional expenses such as illness, the expenses shall be decided by both parties through consultation.