Junior high school math score teaching plan 1
First, the teaching objectives
1. Make students understand and master the concept and rational expression of scores;
2. Ask students to find out the conditions for meaningful scores;
3. Cultivate students' ability to solve problems by using analogy transformation thinking method through the teaching of analogy score research score;
4. Through the teaching of analogy, cultivate students' re-understanding of the dialectical view that things are universal connection and change and development.
Second, the key points, difficulties, doubts and solutions
1. The denominator of the fixed score of teaching key and difficult points is not zero.
2. Doubts and solutions By analogy with the meaning of fractions, we can strengthen our understanding of the meaning of fractions.
Third, the teaching process
Introduction of new curriculum
The factorization problem learned earlier is to decompose algebraic expressions into products of several factors, but if there are the following problems: a classmate
I do 60 sit-ups every minute. How many do I make every minute? Is this an algebraic expression? Let a classmate try to give it a name and say how you came up with it. Students have experience in fractions and can guess fractions. )
New lesson
Definition of 1. score
(1) Students discuss the definition of scores in groups. The division of two algebraic expressions is called a fraction? Mistakes, such as counterexamples, are corrected by students one by one and come to the conclusion:
(2) Students give several examples of scores.
(3) Students should pay attention to the problems in summarizing the concept of scores.
The denominator contains letters.
Like fractions, the denominator of fractions cannot be zero.
(4) Q: When is the score zero? [Take (2) the scores cited by middle school students as an example to discuss]
2. Classification of rational expressions
Let the students compare the classification of rational numbers to the classification of rational numbers;
Classroom practice
Eight, homework
Group A 3 and 4 in textbook P56; Group b (1), (2) and (3).
Nine, blackboard writing design
Project example 1
1. Definition Example 2
2. Reasonable classification
Junior high school math score teaching plan II
Review of math scores in senior high school entrance examination
The combination of classroom-based review teaching and practice
Teaching objectives (knowledge, ability, education) 1. Understand the concepts of fraction and fractional equation, and further develop the sense of symbol.
2. Mastering the basic properties of fractions, performing four operations of fractions, such as reduction, division, addition, subtraction, multiplication and division, etc., to cultivate students' rational reasoning ability and algebraic identity deformation ability.
3. Be able to solve some practical problems related to scores, and have certain ability to analyze and solve problems and application awareness.
4. Through learning, you can get the common methods of learning algebra knowledge and feel the value of learning algebra.
Significance, nature, operation, fractional equation and its application of teaching key scores
Fractional equation of teaching difficulties and its application
Teaching media learning plan
teaching process
One: preview before class (one): knowledge combing
1. Concepts related to fractions
(1) Fraction: An expression with letters in the denominator is called a fraction. For scores:
(1) When _ _ _ _ _ _ _ _. (2) when _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ (3) only when _ _ _ _ _ _ _ _ _ and _ _ _ _ _ _ _ _ _ _ _ _.
(2) simplest fraction: When the numerator and denominator of a fraction are _ _ _ _ _ _ _ _ _, it is called simplest fraction.
(3) Simplification: Simplifying the numerator of a fraction to _ _ _ _ _ _ _ of the denominator is called the simplification of a fraction. The main step of divisible division of a fraction is to divide the numerator and denominator of the fraction by _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.
(4) Divisibility: Divide several fractions with different denominators into _ _ _ _ _ _ _ _ _ _ _, which is called divisibility of fractions. The key to general division is to determine the _ _ _ _ _ _ _ of several fractions.
(5) Simplest common denominator: The product of the highest power of all factors of each denominator is usually taken as the common denominator, and such common denominator is called the simplest common denominator. When finding the simplest common denominator of several fractions, pay attention to the following points: ① When the denominator is a polynomial, it should generally be first; (2) If the coefficients of all denominators are integers, the coefficients of the simplest common denominator are usually taken; ③ The simplest common denominator can be divisible by the denominator of atomic fraction; (4) If the denominator coefficient is negative, generally first? -? Numbers refer to the front of the score itself.
2. The nature of the score:
(1) Basic property: both the numerator and denominator of the fraction are multiplied (or divided) by the same value of the fraction. Namely:
(2) Symbol rule: change the symbol of _ _ _ _ _ _ _ _, that is:
3. Fractional operation: Note: For simple operation, use fractions.
Basic properties and symbolic methods of fractions
Then:
(1) If the numerator and denominator of the fraction
When the coefficient is a fraction or decimal, it is generally converted into an integer.
(2) If the coefficient of the highest term of the numerator and denominator of a fraction is negative, it should generally be turned into a positive number.
The law of (1) addition and subtraction of fractions: (1) addition and subtraction of fractions with the same denominator, addition and subtraction of numerators; (2) Fractions of different denominators are added and subtracted. First, they are converted into scores, and then calculated according to.
(2) Fraction multiplication and division method: the fraction is multiplied by the fraction, with _ _ _ _ _ _ _ as the numerator of the product and _ _ _ _ _ _ _ as the denominator of the product, and the formula is _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _. Divide the fraction by the fraction, and multiply the divisor by the numerator and denominator of the divisor. The formula is:
(3) The power of the score is _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.
4. The mixed operation order of fractions, first, then, and finally, if there are parentheses, use parentheses to calculate first.
5. Simplify the evaluation questions, pay attention to the problem-solving format, simplify first, and then evaluate the value of letters.
Practice before class
1. True or false judgment: ① If the value of a score is 0, the score is meaningless ()
② As long as the value of the molecule is 0, the value of the fraction is 0 ()
3 when a? 0, score =0 is meaningful (); ④ When a=0, the score =0 is meaningless ()
2. In, the number of algebraic expressions and fractions are () respectively.
7， 1
3. If the values of letters A and B in the score (A and B are both positive numbers) are expanded to twice the original values respectively, then
The value of the score is ()
A. expand to twice the original; B. restore to the original; C. unchanged; D. restore to the original state
4. The result of score reduction is.
5. The simplest common denominator of a score is.
Two: analysis of classic test questions
1. When the score is known as x. _ _ _ _ _ _, the score is meaningful; When x = _ _ _ _ _, the value of the score is 0.
2. If the score is 0, the value of x is ().
A.x=- 1 or x=2 B, x=0 C.x=2 D.x=- 1.
3.( 1) Simplify before evaluating:, where.
(2) Simplify first, and then ask you to choose a reasonable value to find the original value.
(3) Known, the value of.
4. Calculation: (1); (2) ; (3)
(4) ; (5)
5. Read the calculation process of the following questions:
= ①
= ②
= ③
= ④
(1) From which step did the above calculation process go wrong? Please write down the code of this step.
(2) The reason for the error is that.
(3) The correct conclusion of this question is.
Three: after-school training
1. When x takes any value, the score (1); (2) ; (3) meaningful.
2. When x is taken, the score (1); The value of (2) is zero.
3. Write the numerator or denominator in brackets in the following equation.
( 1) ; (2)
4. If, then =
5. known. The value of the score is.
6. Simplify the algebraic expression first, and then let you take a set of values of A and B for evaluation.
7. Given that the three sides of △ABC are A, B, C and =, try to determine the shape of the triangle.
8. Calculation: (1); (2)
(3) ; (4)
9. First read the following article, and then answer the questions:
Known: equation equation
Equation equation
Question: Observe the above equation and its solution, then guess the solution of the equation: x- 10 = 10, and write a test.
10. Read the following problem solving process, and then solve the problem:
It is known to find the value of x+y+z y+z.
Solution: let =k,
Answer the following questions according to the above method: Known:
Four: Summary after class
Junior high school math score teaching plan 3
Cognitive score (1)
First, the introduction of questions:
1. This is called a fraction.
2. For any score, when it is not 0, the score is meaningful.
3. When the score is 0 instead of 0, the value of the score is 0.
Second, the basic training:
1. Among the algebraic expressions ①, ②, ③ and ④, there is a fraction ().
A.①② B.③④ C.①③ D.①②③④
2. Score. At that time, the following conclusion was correct ()
A. the value of the score is zero; Scores are meaningless.
C If the score is zero; D If, the value of the score is zero.
3. Among the following items,,,,, 0, _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _; Is the algebraic expression _ _ _ _ _ _ _ _?
4. In time, scores are meaningless.
Third, this example shows that:
Example 1: (1) When = 1, 2, find the values of the scores respectively;
(2) What value is the score meaningful?
Fourth, the classroom test:
1. In the following categories, the possible value of zero is ().
A.B. C. D。
2. In the following categories, the score is meaningful no matter what the value is ().
A.B. C. D。
3. When _ _ _ _ _, the score is meaningless.
4. When _ _ _ _ _ _, the value of the score is zero.
5. Make the score meaningless, and the value of x is ()
1 C. D
6. Solution: When the value is known:
The value of (1) is zero; (2) The score is meaningless.
7. The following scores are meaningful when taken.
( 1); (2).
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