在排列组合问题中有这样一类“球与盒子”问题,把一些小球投入到几个盒子中,给出一定的限制条件,求有多少种不同的方法.我们可以把这类“球与盒子”问题作为一种具体形象的数学模型,帮助我们解决多种多样的排列组合问题.下面分类例析,希望有助于同学们理解具体数学模型的作用,提高迁移运用方法的能力. There are a number of “ball and box” problems with permutations and combinations, putting a few balls into several boxes, giving some constraints and asking how many different ways we can. The problem of “ball and box” as a concrete mathematical model helps us solve a variety of permutations and combinations. The following classification and analysis, hope to help students understand the role of specific mathematical model to improve the use of migration methods ability.