This unit is taught on the basis of "space and graphics", including: the preliminary understanding of quadrangles and parallelograms, the significance of perimeter, the exploration and application of formulas for calculating the perimeter of rectangles and squares, and the estimation of physical objects.

This unit is divided into three sections. The first paragraph is mainly a preliminary understanding of quadrilateral and parallelogram. The meaning and calculation of the main teaching perimeter in the second paragraph. The third paragraph mainly talks about the estimation of the length of some objects, with the aim of cultivating students' estimation consciousness and ability. The specific arrangements are as follows.

In the arrangement, on the one hand, the textbook pays attention to excavating the internal relationship between geometric knowledge; On the other hand, provide a large number of materials closely related to the concept of space, follow the law of children's learning mathematics, and choose active presentation methods to strengthen the content of the concept of space.

The specific content and requirements of the title

Theme map campus scene map. Enrich students' perceptual knowledge of quadrilateral.

Quadrilateral distinguishes quadrangles from various figures and identifies their characteristics.

Parallelogram combines life situation and operation activities, so that students can realize the characteristics of parallelogram's easy deformation, as well as its connection and difference with other quadrilaterals, initially establish the representation of parallelogram, and draw parallelogram on paper.

Perimeter uses physical objects and some figures to explain the meaning of perimeter, so that students can further deepen their understanding of perimeter in practical operation.

The perimeters of rectangles and squares create problem situations, so that students can discover and master the calculation methods of the perimeters of rectangles and squares in their exploration activities.

Ask the students to estimate the length of some objects by drawing a picture, cutting it, estimating it and measuring it.

Teaching suggestion

For a long time, the content and goal of Geometry course mainly focused on the calculation of length, area and volume in primary school, and less involved in three-dimensional space, which failed to develop students' spatial concept and imagination. The standard expands the former "geometry" to "space and figure", which is a major change in the content of traditional mathematics curriculum in China and conforms to the trend of international mathematics curriculum reform. For this reason, the textbooks in primary school weaken the calculation of the perimeter, area and volume of simple plane graphics, strengthen the connection with students' life experience, increase the content of graphic transformation and position determination, and strengthen the process of geometric modeling and exploration. In this way, the course content is organically combined with students' life experience and integrated with all branches of mathematics curriculum, with the purpose of better embodying the educational value of "space and graphics", enabling students to better understand, understand and grasp the space on which they live, and developing students' spatial concept and reasoning ability. Therefore, in the teaching of this unit, we must pay attention to the following points:

1. Pay attention to students' life experience and provide rich perceptual materials.

As mentioned above, promoting the development of students' concept of space is an important task in the teaching of mathematical geometry in primary schools. The world and things that students live in are mostly related to space and graphics, and their life experience is a valuable resource for developing the concept of space. Many subjects closely related to students' life are selected as teaching materials, such as the campus sports scene as the unit theme map, and the scene of a child moving a sliding door as the introduction material of a parallelogram. In teaching, we should give full play to the role of these materials, pay attention to students' existing life experience, expand our horizons from the classroom to the space of life, guide them to observe life, and find problems about space and graphics from the real world.

2. Pay attention to mathematical practice and highlight the process of geometric inquiry.

The concept of space is gradually established in the process of activities. Recalling life experience, observing objects, operating by hands, imagining and describing situations are all ways to cultivate and develop students' concept of space, and are also important means for students to understand abstract mathematics. Because the preliminary knowledge of geometry, whether it is the characteristics of lines, planes and bodies, or the characteristics and properties of graphics, is relatively abstract for primary school students. While providing a large number of vivid and perceptual materials, the textbook adopts a variety of active presentation methods, such as quantity, folding, ratio, painting, pendulum and spelling. In teaching, teachers should give students enough time and space to engage in mathematical activities according to the characteristics of junior students, so that they can experience the process of abstracting geometric figures from real space and exploring the characteristics of the figures and their changing rules through observation, operation, organized thinking and communication, so as to obtain a clear, vivid and vivid understanding, and then form a representation and develop the concept of space.

3. Understand the characteristics of textbook arrangement and properly grasp the teaching requirements.

Students' understanding of some knowledge is often not completed at one time, and needs to be deepened and improved step by step. Therefore, according to students' age characteristics and cognitive ability, the textbook adopts the structure of gradual expansion and spiral rise, and arranges the content of "space and graphics" in different learning periods in a balanced way, and each learning period has corresponding goals. This not only highlights the learning focus of each grade, but also pays attention to consistency. As for the understanding of parallelogram, the textbook is written in two paragraphs. This unit is the first time. Students are only required to identify which parallelogram is from a specific object or figure, and have a preliminary intuitive understanding of its characteristics. The second time will appear in the second period, requiring students to understand that two groups of parallelograms with parallel and equal opposite sides are parallelograms. It can be seen that the same content has different teaching requirements at different stages.

On the other hand, textbooks use different expressions in different years. Take common mathematical concepts as an example. In primary school, although descriptive expression and definitional expression are two main ways of expression (definitional expression is a way to reveal the connotation or extension of a concept in a concise and complete language, and descriptive expression is a way to describe the concept in a vivid and concrete language), descriptive expression is widely used in lower grades and gradually adopted in middle grades. In the whole primary school stage, most concepts are not strictly defined, but based on actual examples or existing knowledge and experience to help students understand the essential attributes of concepts. So is the arrangement of the teaching materials in this unit. There are no strict definitions of quadrilateral, parallelogram and perimeter, as long as students can explain the meaning of perimeter with concrete objects or figures. For the calculation of the perimeter of rectangle and square, the textbook has not yet summed up the corresponding calculation formulas (length+width) ×2 and side length ×4 respectively. The purpose is to let students have a process of independent thinking, constant perception and comparison of calculation methods on the basis of understanding, so as to avoid the phenomenon of rigid formulas.

Therefore, in specific teaching, we should seriously study the standards, carefully analyze the teaching materials and properly grasp the teaching requirements. Prevent arbitrary demands, or let students memorize concepts, formulas, etc.