(1) Drawing basis: ① Basic properties of translation: the connecting lines of corresponding points are parallel and equal. (2) Translation mapping step: (Take the translation map △DEF of △ABC and the corresponding point D of known A as an example. (1) Connect the target point D with the known point A to form a parallel BM with the line segment AD _ 2 passing through the point B and the point C respectively as AD. CN _ 3 intercepts BE=AD and CF = AD _ 4 on BM and CN respectively, and then connects DEF in turn.
In the process of "translation", students should "be able to translate simple graphics horizontally or vertically on grid paper". Students often make mistakes when drawing, especially when they need to count the translated squares. For example, the touching result of smiling in the first 1 question of this class is a typical student's wrong thinking (as shown below).
The best way to solve this problem is to operate more. For example, let students cut a piece of cardboard with the same size as the graphics to be translated, translate it on grid paper as required, and then draw it on grid paper. Then guide the students to observe how a point or an edge is translated as required.
In the operation process, it is very important for teachers to guide students to grasp some key points. Generally speaking, after many operations, students will gradually realize that the difficulty of drawing will be broken by calculating squares and finding points. When necessary, teachers can also "slow down" the translation process, so that students can observe the changes of graphic positions after translating 1 block, 2 blocks and 3 blocks. ...
Finally, for translation and rotation, whether in primary school or junior high school, it is intuitively understood that translation and rotation make the figure move. In different movements, the corresponding points of the figure follow certain changing rules.
Understanding the transformation of graphics is very important for students to understand the colorful real world, form a preliminary concept of space, and feel and appreciate the beauty of graphics. Students can draw translated graphics with the help of grid paper, which is helpful for students to establish a preliminary understanding of the relationship between graphics and enrich the concept of space.
Therefore, teachers should accompany students, accumulate corresponding experience bit by bit, lead students to perceive and experience things around them more comprehensively, know and understand graphics, gradually form the concept of space, and develop logical thinking ability and rational reasoning ability in specific mathematical activities.