数学来源于生活又服务于生活.通过研究性学习与社会实践,我们不但可以找到数学概念在生活中的原型和数学规律在生活中的实例,而且可以学会用数学“语言”描述生活,建立解决各种问题的数学模型.一、洗衣服问题我们用肥皂洗好衣服时,需要把水分挤出来,但不可能把水挤干,衣服中还残留着一定量的水分.假设挤出水分后的衣服上还残留含污物的水1千克,现用20千克清水洗涤.假设在每次洗涤时污物都能充分均匀地溶于水中,问怎样洗涤衣服才能更干净?二、构造模型,解决问题把衣服放到20千克清水中,连同衣服上那1千克污 Mathematics comes from life and serves life. Through research learning and social practice, we can not only find the prototypes of mathematical concepts in life and examples of the laws of mathematics in life, but also learn to describe life in terms of mathematics, “language”. Establish a mathematical model to solve various problems. First, the laundry problem When we wash clothes with soap, we need to squeeze out the water, but it is impossible to squeeze the water, there is still a certain amount of moisture in the clothes. Assuming that the extrusion of water After the clothes still contain 1kg of dirt-contaminated water, which is now washed with 20kg of clear water. It is assumed that the dirt can be fully and uniformly dissolved in the water in each wash, and how to wash the clothes can be cleaner? Second, the structural model To solve the problem and put the clothes into 20 kg of clear water, together with the 1 kg of the clothes