本册教材的教学内容有:小数的意义和性质、小数的加法和减法、四则运算、运算定律、三角形、图形的运动、观察物体、平均数与条形统计图、数学广角及综合与实践活动等。其中,小数的意义和性质、小数的加法和减法、运算定律以及三角形是本册教材的重点教学内容。下面,主要从修订变化的角度对本册内容作简要介绍。一、四则运算与实验教材相比,本单元的编排有两点较大的变化。1.增加了四则运算的意义和每种运算各部分间的关系整数四则运算的意义是学习小数、分数四 The content of this book's teaching materials are: the meaning and nature of decimals, the addition and subtraction of decimals, the four arithmetic, the law of operation, the triangle, the movement of the figure, the observation object, the average and the bar chart, the wide angle of mathematics and the synthesis and practice activities Wait. Among them, the meaning and nature of decimals, addition and subtraction of decimals, arithmetic law and the triangle is the focus of teaching content of this book. The following, mainly from the perspective of changes in the content of this book a brief introduction. One or four operations compared with the experimental teaching materials, the unit's layout has two major changes. 1. Increase the meaning of the four operations and the relationship between each part of each operation Integer The meaning of the four operations is to learn the decimal fraction of four