2. Analysis of learning situation: It is difficult for students to touch division when they are young, and it is necessary to understand the significance of division through the intuitive demonstration of multimedia teaching and the number of students' hands.
Teaching objectives:
1, combined with the specific situation and experience of average score, abstract the division formula and realize the significance of division operation.
2. Master the reading and writing of the division formula and know the names of each part of the division formula.
3, will use the division formula to express and explain the specific process of average score.
4. Cultivate students' ability of problem solving and mathematical thinking.
Key points: the reading and writing method of division formula, the names of each part and the significance of division.
Difficulty: the process of dividing into equal parts.
Teaching preparation: multimedia teaching instruments and self-made courseware
Preparation of learning tools: 12 banana pictures, 1 bag sticks.
Teaching process:
First, the creation of situations
Students, have you ever had guests in your family? What do you usually entertain guests with?
You are really warm and polite children. Do you know, today, this wise old man brought two special guests, neither playful nor clever dogs, but two cute little monkeys. The clever old man took out big and long bananas and gave them lunch. How many bananas are there? How do you know that? How do two little monkeys share 12 bananas? (Average score) Who can say what an average score is? The wise old man wants to invite the children in our class to help divide bananas. Would you like to? Ok, in this lesson, we will learn how to divide bananas.
Second, the problem situation
Activity 1: replace bananas with sticks and score one point.
1, please use school tools instead of bananas.
2. Who will tell me your score results?
What if we don't have school tools? Is there any other way for you to divide 12 bananas into two equal parts, each with 6 bananas?
4. You are really something. You know, divide a thing into several parts and work out how much each part costs. Can be calculated by division.
(Screen display: 12÷2) ÷ What's your name? What does the division symbol look like?
There is a cross in the middle, with a dot on it and a dot on the bottom, which are the same size and neatly arranged. Lead the students to read it twice-Division)
4. How to read the division formula and the names of the parts?
What does 12 mean? What does this 2 mean?
"12" is the average of bananas, written before the division symbol. "2" refers to the number of shares distributed equally. Write it after the division symbol.
Look, how neat our division formula is. It can be said that 12 bananas are divided into two parts on average. Do you know how to pronounce this division formula?
The division formula is: 12 divided by 2. (Read it twice. The result is "6 pieces each", and "6" is written after the equal sign.
Bananas are divided. What should be the name of the company?
5. practice. How to read the division formula? Look at the picture and say the division formula. )
Everyone reads very neatly. So, can you read the following division formula?
I can read.
6÷2 10÷5 18÷4 20÷5
Everyone reads so loudly. We already know that when something is divided into several parts, it is calculated by division.
Activity 2: Divide 12 bananas into 3 parts, each with 4 bananas.
1. If today, the clever old man came with three monkeys instead of two, how about 12 bananas? I think everyone can do it. Students in the group will come together. The team leader will do a good job in division of labor and organization. One person will give ideas, one will draw pictures and the other will write division and calculation formulas. Compare which group has more divisions and whose division formula is the most beautiful.
Student communication operation: speaking, dividing and writing.
Blackboard: 12÷3=4 (root) What does the formula mean?
Students, in the division formula, the division doll already has its favorite name-division, (screen display: division)
Do you know that?/You know what? Do you know that?/You know what? Other numbers in the division formula also have their own nice names. Do you know that?/You know what? Do you know that?/You know what?
(1) The total number of bananas before the divisor "12" is called the dividend.
(2) The "2" after the divisor indicates that it is evenly divided into two parts, which is called "divisor".
(3) The result of "6" after the equal sign is called "quotient".
Activity 3: Exchange other ideas in the group.
12 bananas are divided into two or three parts on average. How many parts can you share equally?
① Divide 12 bananas into 4 parts, each with 3 bananas. Formula: 12÷4=3 (root)
② Divide 12 banana into 6 parts, each with 2 bananas. Formula: 12÷6=2 (root)
③ Divide 12 banana into 12 portions, each portion is 1, and the formula is: 12÷ 12= 1 (root).
Teacher: Students are really smart. It is amazing that they can divide 12 banana into so many different shares and list so many neat division formulas. This is a new lesson we learned today. Please open the textbook P38- Divide bananas. Everyone enjoys learning while playing. So, what do you know that makes you particularly happy? What have you learned that makes you particularly happy?
The teacher concluded: Today we all know the division and divisibility formulas.
Third, consolidate and deepen.
1, help the rabbit divide the wood.
(1) The Bunnies are decorating their house in the big forest. It wants to divide 18 piece of wood into two parts equally, but it can't figure out how many pieces there are in each part. Can you help it? 18÷2=9 (root)
(2) 18 A piece of wood can be divided into two parts on average. How many parts can it be divided into?
18÷3=6 (root); 18÷6=3 (root); 18÷9=2 (root)
2. Help the hedgehog divide the fruit.
(1) Look at the pictures carefully and ask math questions. (12 fruits are distributed to 4 hedgehogs on average. How much fruit does each hedgehog bring? )
(2) According to the chart calculation formula, tell how you know the quotient.
Fourth, the practical application: