1, to further understand the meaning and difference between perimeter and area of plane graphics. Make students understand the derivation process of formulas for calculating the perimeter and area of plane figures, and use these formulas to make correct calculations.

2. Make students form a knowledge system about the perimeter and area of plane graphics.

3. Infiltrate the idea of transformation and use this idea to solve some practical problems in life.

Teaching emphasis and difficulty: review the calculation formula and derivation process, and skillfully use the formula to calculate.

Instructional design:

First, import

1. Recall the plane graphics you have learned.

Students, what plane graphics have we learned? Show the plane figure after the students answer.

We already know their perimeter and area. Today, let's review together.

Second, organize review.

1. The concepts of perimeter and area.

(1) What is the perimeter and area of a plane figure? Who can choose any number to say? Call the students to the front to demonstrate.

(2) So, who can tell me about the perimeter of a plane figure? Write on the blackboard after the students answer: the sum of all sides of a figure is called the perimeter of the figure.

(3) We use length units to represent the perimeter of a graph. Who can tell us which units of length we have learned? What is the forward speed between them? (Students recall and complete the 1 question of "Practice and Practice". )

(4) What is the area of the plane figure? Write on the blackboard after the students answer: the size of the surface or closed plane figure of an object is called their area.

(5) We use the area unit to represent the area of a plane figure. What units of area have we learned? What is the forward speed between them? (Students answer and complete the second question of "Practice and Practice". )

(6) Complete the third question of "Practice and Practice".

2. Comparison of perimeter and area.

We already know the meaning of perimeter and area. Teacher, here are two pictures. Please compare them separately.

Their perimeter and area. Show the fifth question "Practice and Practice". )

(1) If each cell in the diagram is a square with a side length of 1 cm. Please observe these two sets of figures carefully in groups and discuss these two issues seriously.

(2) Report: What did you find through observation and discussion? how do you know (Let the students point and say)

① The first picture: the area is equal, but the circumference is unequal.

② The second picture: The circumference is equal, but the area is unequal.

(3) Summary: Visible perimeter and area are not necessarily related.

3. Calculation formula of perimeter.

Do the students remember how to calculate the perimeter of these figures?

(1) The calculation method of remembering plane figures at the same table.

(2) Tell the formulas for calculating the perimeter of rectangles and squares.

(3) Let some students talk about the derivation process of the formula of circumference.

4. Area calculation formula.

We have recalled the calculation method of the perimeter of plane figures together, so how are the area formulas of these plane figures derived?

(1) Ask the students to discuss the following two questions in groups and show the relationship between them with six plane figures.