# Teacher Recruitment # Introduction For students who enter the interview but don't know where to start reviewing, there is only one problem: improve their audition ability and skills quickly. Prepare a trial teaching plan for candidates' reference.

First, the teaching objectives

1, knowledge and skills: master the positive and negative usage of the square difference formula;

2. Process and method: Learn to find "=" in calculation through algebraic operation and geometric derivation;

3. Emotion, attitude, values: Combined with the derivation process of the formula, I feel the help of the square difference formula for calculation and truly appreciate the charm of fast calculation.

Second, the difficulties in teaching

1, key point: master the positive and negative usage of square difference formula;

2. Difficulties: Find out the laws in the multiplication of algebraic expressions and understand the changing characteristics of "=" in the formula.

Third, teaching support conditions (teaching methods)

Multimedia (PPT dynamic display, geometric sketchpad), cooperative inquiry method, and teaching method.

Fourth, the teaching process

1, course introduction: review the past and learn the new, and put forward the following questions in combination with the first section:

Question 1: Calculate the multiplication of the following algebraic expressions.

(k+2)(k-2)(m+2)(m-2)

(x+3)(x-3)(a+b)(a-b)

Question 2: Combining the four formulas, please feel free to observe the characteristics of the left and right sides of "=" in the formula.

2, new teaching: a competition, four students are divided into one group, the whole class gives the following formula to calculate, to see which group completes quickly:

Premise: In the independent calculation, some students found certain rules in the previous calculation and observation, so they can finish the calculation quickly, and this rule will be reflected in the group and between groups. Because of the urgency of the competition, there was the first communication between fast and slow students in the group.

After the game, I will throw a question:

Question 1: After the calculation just now, tell me what rules you found.

Question 2: Which formula do you think can present this rule in the calculation just now?

Question 3: Can you describe the square difference formula in words?

Question 4: What are the characteristics of the square difference formula?

3. Consolidate new knowledge and apply it.

Combine the picture above (left) and ask questions.

Question 1: Calculate the shadow area in the drawing?

Default 1: students find two methods, and ask them to tell the rules they have found by combining the "square difference formula";

Premise 2: Students try to guide students to cut the figure and understand it (right), and also use the "square difference formula" to talk about understanding.

Question 2: Please describe the geometric description of the mean difference formula accurately.

Then do consolidation exercises. Deepen memory.

Step 4 summarize your homework

Summary question 1: Let the students who have just calculated slowly recall the company and then dictate a question;

Question 2: Let the students talk about the benefits of learning the square difference formula.

Homework: exercises after class

Five, the blackboard design