It may not be in the contract. Generally speaking, I write the details of the house. According to the laws of our country, the house contract is the buying and selling relationship between you and the developer of the sales office, and the real estate license is the ownership relationship of the house property. Commercial housing sales contracts do not necessarily have the serial number of the real estate license. If not, you can ask the number of the seller's real estate license. Or you can go to the Housing Authority for enquiries.
The room card number refers to the record number, which should be inquired by the Housing Authority. Buying a house 1 or 2 months, the Housing Authority has put on record the number. If you swipe your ID card on the machine, a message about your purchase will come out. The record number written in the first one may be six digits.