锐角和钝角是人教版教材二下年级的内容,在这之前学生在二上年级已经学习了直角,会用三角板上的直角来验证直角,并能用直角三角板画直角。本课教材的编排是先从现实生活中的斜拉桥提取出三种角,然后认识比直角小的角是锐角,比直角大的角是钝角,接着是折直角、用活动角摆出锐角和钝角,最后是 The acute and obtuse angles are the content of the second grade of the PEP textbook. Prior to this, students had studied right angles in the second grade and would use right angles on the triangles to verify right angles and right angles to the right angles. This textbook choreography is to extract three angles from the cable stayed bridge in real life, and then recognize that the angle smaller than the right angle is acute angle, the angle larger than the right angle is the obtuse angle, then the right angle and the acute angle And obtuse, the last is