学习本课前,学生已较熟练地掌握了一步计算的加、减法实际问题,也已基本掌握了三位数加、减三位数的计算方法,这些知识都是学习本课新知识的基础。学习解决需要两步计算的加、减法实际问题,能够进一步提高学生的分析、综合和推理能力,又能为后继教材中解决实际问题的学习奠定基 Before studying this course, students have mastered the practical problems of adding and subtracting one-step calculation more skillfully. They have also mastered the calculation methods of three-digit plus and minus three-digit, which are the basis of learning new knowledge in this course. . Studying and solving the practical problems of adding and subtracting, which need two-step calculation, can further improve students’ ability of analyzing, synthesizing and reasoning, and can also lay a solid foundation for the study of solving practical problems in the following textbooks