求随机事件的概率是排列组合等知识的重要应用.由于其中涉及的知识点较多,同学们在解这类问题时普遍存在着“会而不对”的现象,即想起来简单而算起来出错.主要原因有题意领会不全、概念不清、考虑不周、错用公式、错建模型等.本文准备对同学们概率计算中常见的几种“忽视致误”进行剖析.一、审题不清例1高三(1)班、高三(2)班各选出了 The probability of finding random events is an important application of knowledge such as permutation and combination. Because there are many knowledge points involved, students generally have the phenomenon of “what if not right” when solving such problems. It’s an error. The main reasons are misunderstanding of concepts, unclear concepts, ill-considered, wrong use of formulae, wrong construction of models, etc. This article is intended to analyze the common types of “ignorance caused by mistakes” in classmates’ probability calculations. I. Unclear Example 1 High School (1) and Senior 3 (2) classes were selected