Proportional relationship: in cooking, the proportion of ingredients in recipes is usually calculated according to the amount of food. For example, how many cakes can be made with two eggs and 1 cup of flour? It needs to be calculated according to a certain proportion.

2. Quantity relationship: When buying food, quantity is usually an important consideration. For example, to buy fruit, we need to consider the relationship between quantity, weight and price to determine the most cost-effective purchase plan.