This lesson is selected from the first section of Unit 5, Volume 2, Grade 2, Primary School Mathematics, Beijing Normal University Press, which is actually an understanding of millimeters and decimeters.

Students already know centimeters and meters, as well as simple estimation and calculation, in the second half of senior one. On this basis, this unit further studies other length units: kilometer, millimeter and decimeter, grasps the simple conversion between them, and feels the actual length between 1 decimeter, 1 millimeter and 1 kilometer. It paves the way for understanding the perimeter and calculating the perimeter of rectangles and squares in the third semester.

The first volume of the second grade mathematics of Beijing Normal University; The instructional design of "How long is 1 meter"; Teaching objectives: to know the meter in observation and measurement activities, understand the practical significance of the meter, and initially learn to measure the length of objects with meters (limited to whole centimeters); Experience the significance of measuring length in daily life in measuring activities;

Key points: the practical significance of rice and the relationship between rice and centimeter; Difficulties: choose the right unit to represent the length of the object; Teaching preparation: PPT courseware and three-meter ruler; 1. Introduction: We studied last class.

Understand the meter in the observation and measurement activities, understand the actual meaning of the meter, initially establish the concept of the length of 1 meter, master 1 meter = 100 cm, and carry out simple unit conversion. At first, I learned to measure the length of an object in meters (limited to whole centimeters), estimate the length of the object, and choose the appropriate unit to represent the length of the object.