Mathematical model of urban and rural residents' consumption behavior. 2. Establish a mathematical model to find out the main factors or indicators that affect the consumption difference between urban and rural residents in Chengdu. 3. Use mathematical model to analyze whether the consumption difference between urban and rural residents in Chengdu has expanded, narrowed or remained unchanged in recent years. 4. Consumption structure refers to the proportional relationship between different types of consumption materials (including labor services) that people consume in the process of consumption under certain social and economic conditions. Please establish a mathematical model about the changes of consumption structure of urban and rural residents in Chengdu from the perspective of consumption structure, and predict and simulate the changes of consumption structure of urban and rural residents in Chengdu in the next three years according to this model. 5. According to the established mathematical model and results, some suggestions are put forward to narrow the consumption gap between urban and rural residents in Chengdu.