1, combined with specific things or graphics, through observation, operation and other activities to understand the perimeter.

2, can measure and calculate the perimeter of triangle, parallelogram, trapezoid and other graphics.

3. Be able to perceive the close connection between circumference and real life in combination with specific situations.

Teaching emphasis: Understand the meaning of perimeter, and be able to measure and calculate the perimeter of triangle, parallelogram and trapezoid.

Teaching difficulty: understanding the meaning of perimeter.

Teaching preparation:

Ppt courseware, multimedia courseware, leaves, lines, rulers, tape measures, draft books, crayons, textbooks.

Teaching process:

First of all, the introduction of passion

First,? Introduce dialogue and reveal the topic.

Q: Students, do you know what the circumference is? How to understand the word perimeter?

Second, through operation, concrete perception.

1, touch, first operation, forming perception.

Teacher:

(1) In science class, we learned Leaves of Plants, which is about leaves. Look, these are all kinds of leaves collected by the teacher. Are these leaves beautiful? (Courseware demonstration, physical display)

(2) How many parts does a leaf consist of? Where is the perimeter of the leaves? (Let students touch with their hands)

(3) Name three students, let them demonstrate one by one, and ask them to move slowly and clearly;

Make a request: carefully observe each student's demonstration. What did you find? (Students answer, the teacher writes it on the blackboard)

A. where to start and finally go back, uninterrupted;

B.they all touch along the edge of the leaves.

(4) Who can say what the perimeter of the leaves is? (Students answer, the teacher writes it on the blackboard)

The length of a week along the edge of a leaf is the perimeter of the leaf.

2. Draw traces and operate again to deepen perception.

(1) Please select a leaf and try to draw its circumference.