崇仁1、组合图形的面积 - 光泽县崇仁新华中心小学-网站首页（1, the area of the combination of graphics - sheen County Chongren Xinhua Central Primary School - home page）

1、组合图形的面积-光泽县崇仁新华中心小学-网站首页1, thearea of the combination of graphics - sheen County Chongren

Xinhua Central Primary School - home page

Area of a composite graph

The first class: the area of the combined graph

Teaching objective

1, knowledge and skills

(1) in the activities of independent exploration, understandthe method of calculating the area of combined graphics.

(2) according to the conditions of various combinations ofgraphics, the calculation method can be effectively selectedand the correct answer can be made.

(3) can use the knowledge learned to solve the actual problemsof combination graphics in life.

2, process and method

Let students cooperate and communicate on the basis ofindependent exploration, so as to sum up the calculation methodof the area of combined graphics.

3, emotions, attitudes and values

(1) combined with specific examples, it is necessary to

calculate the area of combined graphics and produce positivemathematical learning emotion.

(2) mathematical thought and method of inf iltrationt ran sformat i on.

Heavy, difficult and key

1, teaching key points: according to the conditions to seek thearea of the combination graphics, master the calculation methodof the area of the composite graphics.

2, teaching difficulties: understand the method of calculatingthe area of combined graphics.

3, teaching key: calculation method to use the combination ofgraphics "segmentation" and "fill" area.

Teaching aids and learning tools

Prepare several rectangular, square, triangle, parallelogram,trapezoidal and other graphics of the paper.teaching process

First, understanding the combination diagram in the jigsawpuzzle activities

1, students, we have known the rectangle, square, triangle andparallelogram, please come up with rectangular, square, pleasespell a complex figure with these figures, and say what say

like.

2, ask students to spell out a variety of graphics, introducedto you: what do you spell like graphics?

Two. Searching for calculation methods in explorationactivities.

1. The teacher displays the figure, the student observes thegraph which the teacher produces, this picture resembles any.

2. Raise questions

Do you know how many square meters of floor you should buy?

3. Autonomous exploration algorithm

(1) let the students estimate the floor area first,

(2) how to calculate the exact number?

The students begin to write and communicate with each otherwithin the group. The teacher visits the camera to guide thestudents.

4, the whole class exchange algorithm.

When communicating, the teacher asks the students to say whatthey think, and how to count them.

5. Inductive algorithm.

Teacher: through the discussion just now, what do you thinkshould be done to calculate the area of the combined graph?Discuss, to guide students to understand: the calculationmethod of the combination of graphics area which can be "split"and "fill" calculation.

Three, grasp the method in practice feedback.

The teacher selects the typical student puzzle, studentobservation, independent calculation of the area of thecomposite graphics and feedback.

Four. Summary of the whole lesson

What do you learn from this lesson? Where is the areacalculation of combinatorial graphs in life?

Five, homework design

(1) complete the textbook".

(two) solve the problem

There is a wall, known per square meter with 0.8 kilograms ofpaint, ask: paint this wall how much paint?

4m

5m

Second class hour: the area practice course of combinedgraphics

Exercise content

1, 2 and 3 questions of "seventy-sixth exercises" in textbookPractice goal

1, knowledge and skills

(1) through practice, further understand and master a varietyof methods to calculate the area of combined graphics.

(2) according to the characteristics of various combinationsof graphics, choose the appropriate method to calculate thearea.

(3) can use the knowledge learned to solve the actual problemsof combination graphics in life.

2, process and method

Let the students experience the process of diversification ofalgorithm, in the process of independent thinking andcooperation in society further use of the "segmentation" and"fill" the calculation of the combination of graphics area.3, emotions, attitudes and values

(1) in the process of solving the problem, to further understandthe close relationship between mathematical knowledge and reallife, so as to produce the desire to explore.

(2) understanding the importance and necessity of cooperativelearning in the process of communication algorithm.

Practice process

First, review the introduction, reveal the subject

1, review the content of the last lesson, talk about thecharacteristics of the composite graphics, and seek the methodof the combination of graphics area.

2. Reveal the content of this lesson and write the topic onblackboard.

Two. Guiding practice

1 and first questions

(1) students think independently and divide the graphics theyhave learned.

A, students separate B, display segmentation situation

(2) ask the students to divide the graph into the least learnedgraphics.

(3) add the condition for segmentation.

A, students according to the conditions of B, say why suchpoints

2 and second questions

(1) free reading problems, understand it.

(2) formulation calculation

A, ask for the area of the wall to be painted first

10 x 1.6 / 2 x 410

B, and then figure out how many kilos of paint it will take

0. 15 X 48 = 7.2 (kg)

When communicating, if the students make a comprehensiveformula to calculate, as long as reasonable, teachers shouldalso be affirmed.

3 and third questions

(1) read the question freely and discuss how to solve theproblem of "how much paint is needed. ".

(2) students practice

(3) reporting feedback.

Three. Exercise independently

(1) presentation exercises

1. narrative calculation thinking.

The students discuss with each other exchange.

2. for the upper icon on the data, the area.

Can the students finish after the exchange.

3. narrative calculation thinking.

S umm ary:

First, the combination graph is divided into several basicplane figures, and the area is calculated by the basic figurearea formula, and then the parts are added together.

(two) solving problems

There is an irregular area, such as a graph, if the area is used

0.2 square meters of floor tiles, at least how many tiles?Four. Summary of the whole lesson

What do you learn from the exercises in this lesson?

Five, assignments: seventy-fifth pages of practical activities

2, exploration activities - "footprints of growth"

Teaching content: ninth edition of mathematics textbook ofBeijing Normal University (page 77-78) .

Teaching objective:

1, knowledge and skills: can correctly estimate the size ofirregular graphics area, can use the number square method tocalculate the area of some irregular graphics, master the orderand method of the number grid.

2, the process and methods: by means of grid map estimation ofirregular graphics area, in the process of estimating the areaof experience to solve diversity strategy, develop preliminaryestimate consciousness and estimate the habit, experience thenecessity and importance of estimation.

3, emotion, attitude and values: understand the closerelationship between mathematics and real life, and feel theapplication value of mathematics.

Teaching emphasis: using the grid graph to estimate theirregular figure area.

Teaching difficulties: the choice of habits and methods ofestimation.

Teaching thought: