Well, some are internationally used, and some are statistical signs stipulated by the state. Different numbers represent different food categories. There are also supermarkets that are brushed with bar codes, because those different kinds of food have been entered into the computer in advance to register when they are put into storage. In this way, the method of information system management is adopted, which facilitates the inventory management of goods and can replenish goods in time. As long as the goods are brushed off when they leave the supermarket, the computer system will automatically link with inventory management.