does your backward extrusion method mean that the ingredients purchased by the hotel go directly into the kitchen? At this time, you directly count them into the main business cost according to the amount of the purchase order. If they don't go directly into the kitchen, you directly put them into storage. At the end of the month, the cost is carried forward at one time according to the documents received by the kitchen. You should take inventory of the remaining ingredients in the kitchen at the end of the month, and convert them into an average unit price according to the unit price on the purchase order of the month. This unit price is up to you, which is almost enough. If you really calculate the price according to the weighted average, I estimate that you will be exhausted. For example, if the purchase price of an ingredient is about five yuan for almost several times, you can calculate it according to five yuan, make an inventory table, list the remaining ingredients, and then take your estimated unit price to calculate the total amount (for example, 511). As a backward extrusion method, at this time, you need to take stock of fake storage at the end of one month, borrow 511 items from inventory, and the main business cost (debit in red) is 511. At the beginning of next month, the borrowing cost is 511, and the loan inventory is 511. Personally, I feel that this is enough.