《梯形的面积》是沪教版五年级第二学期的内容。面对这一内容,学生已具备充分的知识基础,其中包括三年级时学习的长方形的面积计算、正方形的面积计算、组合图形的面积计算以及五年级学习的平行四边形的面积计算、三角形的面积计算和梯形的初步认识等。因此,在本节课的教学中,教师完全可以引导学生利用图形的转化,将未知转变成学生的已知,让学生利用已有的知识来解决新的问题。令人欣喜的是,肖老师正是采用了以上方法。当学生的课堂表现超出其预设时,肖老师将学习的时空 “Trapezoidal area” is the second semester of Shanghai PEP. Faced with this content, students already have a good knowledge base, including the third-grade learning rectangle area calculation, the square area calculation, the combination of graphics area calculation and fifth-grade learning parallelogram area calculation, the area of ​​the triangle Calculation and trapezoidal initial understanding. Therefore, in the teaching of this lesson, teachers can guide students to use graphics transformation, the unknown into the student’s knowledge, so that students can use the existing knowledge to solve new problems. The good news is that Xiao is using the above method. When students’ classroom performance exceeds their preconditions, Shaw learns time and space