First, three-dimensional teaching objectives
1. Knowledge and skill goal: Understand the meaning of multiplication and division, understand that division is the inverse operation of multiplication, and master the relationship between the parts of multiplication and division, which will be used in practical calculation.
2. Process and Method Objective: To experience the process of solving problems and cultivate the ability of abstract generalization, migration and logical thinking.
3. Emotional attitude and values: Experiencing mathematics comes from life, stimulating students' interest in mathematics and experiencing the happiness of success.
Second, the focus of teaching
Understand the meaning of multiplication and division, and master the relationship between the parts of multiplication and division.
Third, teaching difficulties
Summarize the meaning of multiplication and division with standardized mathematical language and understand "inverse operation"
Fourth, the teaching process
1, import new knowledge
The teacher showed pictures of vases and asked: (1) How many flowers are inserted in each vase, and four vases? Formula: addition 3+3+3 = 12, multiplication 3×4= 12. Question: Why can we use addition or multiplication? This leads to the topic.
2. New course teaching
Activity 1: Understand the meaning of multiplication and division and some of their names.
First of all, the teacher organizes students to talk at the same table and asks: What is the relationship between multiplication and addition? How can we describe the meaning of multiplication by addition?
Summary: The simple operation of finding the sum of several identical addends is called multiplication; Multiplication of two numbers is called factor, and multiplication is called product.
Secondly, the teacher demonstrated that (2) there are 12 flowers, and one bottle can be inserted into every three flowers. How many bottles can you insert? (3) There are 12 flowers, which are put in four vases on average. How many flowers are inserted in each vase? Formula: 12÷3=4, 12÷4=3. Guide students to observe carefully and ask questions: What are the calculation methods used in these two questions? Compared with question (1), what are questions (2) and (3) known respectively? Ask for what? How to calculate?
Summary: Given the product of two factors and one of them, the operation of finding the other factor is called division. In division, the known product is called dividend, one of which is called divisor and the other is called quotient.
Activity 2: The relationship between multiplication and division.
Teacher's question: Can you sum up the relationship between multiplication and division by formula? Can you tell me the relationship between multiplication and division? What is the relationship between dividend and quotient, divisor and remainder in division with remainder?
Summary: the relationship between the parts of multiplication: product = factor × factor, factor = product ÷ another factor. The relationship between the parts of division: quotient = dividend/divisor, divisor = dividend/quotient, dividend = quotient × divisor. Division is the inverse of multiplication. Dividend = quotient × divisor+remainder.