Hunan Education Edition Grade 8 Volume I Mathematics Teaching Plan (1)
1. 1 score
The concept of 1. 1. 1 fraction
(Lesson 65438 +0)
Teaching objectives
Feel the basic nature of the score through specific situations and draw the basic nature of the score by analogy.
3 understand the conditions for meaningful scores.
Teaching emphases and difficulties:
Key point: the concept and nature of score. Difficulty: understanding the nature of scores.
Hunan Education Edition Eighth Grade Mathematics Teaching Plan Volume I (2)
teaching process
First, create situations and introduce new lessons.
Explore:
1 Give three identical apples to four children. How many apples does each child get? How do you share it with them? (exchange discussion)
(1) for each child.
(2) division method:
① Each apple is cut into four equal parts, *** 12, with 3 parts each, accounting for 3 43 4② For the convenience of each child, each apple is cut into 8 parts, with 24 parts each, with 6 parts each, and these 6 parts account for one apple. eight
3633? 26=) What does this mean? Think about whether these two points get the same amount? (=, that is: =4844? 28
The numerator and denominator of a fraction are multiplied or divided by a number that is not equal to zero, and the value of the fraction remains the same.
The numerator and denominator of the fraction are rounded to a factor of * * *, and the value of the fraction remains unchanged.
This is the basic nature of fractions.
2 (1) changes the above problem into: give n (m >) three identical apples; 0) How many apples does each child get?
333 is expressed by division: 3? N, expressed as a fraction: 3? Is n equal? (3? N=) n here can be nnn
Is it a real number? (n can't be 0) What's the difference between 33 (2) and? (The denominator of the latter contains letters) We call the former a fraction and the latter a fraction, 4n.
What is a score? Are fractions the same as fractions?
In this lesson, we will learn the basic properties of fractions. (blackboard writing topic)
Second, cooperate and exchange, and explore new knowledge.
Fill in the blanks with the concept of 1 fraction;
(1) If Xiao Wang buys B bags of the same melon seeds with A yuan, then the price of each bag of melon seeds is _ _ _ _.
Yuan.
(2) The area of trapezoidal plate is 6 m2. If the upper bottom of the trapezoid is am and the lower bottom is bm, then the height of the trapezoid is _ _ _ _ _ _ _ m. 。
(3) Two paddy fields with an area of A Mu and b mu, m kg and n kg respectively, with an average yield of _ _ _ _ _ kg per mu. A 12m？ N Observation Polynomials: What are the similarities between these algebras? (numerator denominator is algebraic expression, ba? Ba? b
Denominator contains letters)
Generally speaking, if F and G represent two algebraic expressions respectively, and G contains letters, then the algebraic expression F is called a fraction. g
Note: The denominator of a fraction is generally a polynomial, and a monomial can be regarded as a polynomial with only one term. Denominator must contain letters.
Basic properties of 2- fraction
33aa2ba Thinking: Is it equal to the score? Is score 2 equal to score? 44aabb
33aa2baa2ba If A? 0, then =, as long as 2 and both are meaningful, then 2=. 44aabbabb
Do you think scores and scores have the same nature?
The numerator and denominator of a fraction are multiplied or divided by an unequal nonzero polynomial, and the value of the fraction remains the same.
The numerator and denominator of the fraction are divided by the factor * * *, and the value of the fraction remains the same.
Expressed by formula: let h? 0, then ff? h？ gg？ h
3 The condition that the score is zero and the condition that the score is meaningful
Example 1 Find the score x? 52, (1)x=3, (2)x=? x？ 65
x？ 5(x？ The value of 5) is zero, how much should x be equal to? To make the score zero, x? 6(x？ 6)(x-5) Thinking: (1) If it is a score,
What should x be equal to?
What is the condition that the fractional value is zero? (numerator is zero, denominator is not equal to zero)
Example 2 What value does X take, decimal X? 2( 1) is meaningless and (2) is meaningful. 2x？ three
What are the conditions for meaningful scores? (Denominator is not equal to zero)
Hunan education printing plate eighth grade first volume mathematics teaching plan (3)
Classroom practice, consolidate and improve P 3
Reflect and summarize, consolidate and improve. What did you gain from this class?
This paper studies the concept of fraction, the basic properties of fraction, and the conditions that the fraction value is zero and the fraction value is meaningful.
Jobs P6
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