【案例背景】学生在学习的过程中犯错是正常的现象,“错”作为一种另类的教学资源,如果能被老师合理的利用、纵深的探究,能成为学生在学习上的一个起飞点,也能较好地促进学生情感的发展。新《数学课程标准》指出:“要关注学生在数学活动中所表现出来的情感与态度,帮助学生认识自我,建立信心。”良好的数学情感与态度是学生参与数学活动的重要动力,是克服困难和探索创新的力量源泉。一百以内的退位减法的算理和算法是学生理解的重点,也是难点,让学 Case Background It is normal for students to make mistakes in the process of learning. As an alternative teaching resource, “wrong” can become a take-off for students if they can be reasonably utilized and in-depth exploration by teachers Point, but also to better promote the development of emotional students. The new “Mathematics Curriculum Standard” states: “We should pay attention to students’ emotions and attitudes expressed in mathematics activities and help students to recognize themselves and build confidence.” Good mathematical emotion and attitude are important motivators for students to participate in mathematics activities, It is a source of strength to overcome difficulties and explore new ideas. Less than one hundred abort subtraction algorithm and algorithm is the focus of student understanding, but also difficult, so that learning