1. cost: cost = selling price× (1-gross profit margin). For example, the known gross profit margin is 36%, the selling price is 126.36 yuan, and the cost = 126.36× (1-36%) = 81.85 yuan.

2. Gross profit margin: Gross profit margin = (selling price-cost) ÷ selling price× 111%. For example, the known cost is 2.67 yuan, and the selling price is 3.93 yuan. Solution: Gross profit margin = (3.93-2.67) ÷ 3.93× 111% = 32%.

3. selling price: selling price = cost ÷ (1-gross profit margin). For example, the known gross profit margin is 41%, and the cost amount is 24.39 yuan. Solution: selling price = 24.39 ÷ (1-41%) = 41.35 yuan.

In a restaurant, from purchasing raw materials to withdrawing funds, the consumption, price difference, gross profit and actual profit in the process.

customer attendance, average consumption level, salary, inventory, delivery and liquor profit, etc. all need to be accurately calculated.