Teaching plan design of decimal multiplication integer in people's education edition
Decimals in the first category are multiplied by integers.
Teaching objectives:
1, so that students can understand the calculation method and arithmetic of multiplying decimal by integer.
2. Cultivate students' ability of migration and analogy.
3. Feel the application of decimal multiplication in life.
Teaching emphasis and difficulty: understand the calculation method and logic of decimal times integer.
Teaching process:
First, the scene is introduced.
Teacher: Do students like flying kites? Today, the teacher will take the students to fly kites, but before flying kites, we will go to the store to buy kites. There are many kites in the shop. Let's see what kites there are. (Showing multimedia courseware)
①4.6 yuan ②6.4 yuan ③3.5 yuan ④7.8 yuan
Second, teach new lessons.
(A), a preliminary understanding of decimal times integer
1, Teacher: Which one do you want to buy, class? How much should I buy?
After the students scrambled to say what kind of kites to buy and how many to buy, the teacher wrote the different choices of the four students on the blackboard in the form of a table.
kite
unit price
amount
2. According to the students' feedback, Teacher: XX said to buy a kite from 3.5 yuan, so can you accurately calculate how much it costs to buy such three ones?
Students calculate independently.
Answer the forecast:
Methods1:3.5+3.5+3.5 =10.5 yuan.
Method 2: 3.5 yuan =3 yuan 5 jiao, 3 yuan? 3=9 yuan 5 jiao? 3= 15 angle, 9 yuan+15 angle = 10.5 yuan.
Method 3: Calculate the 35 angle with a vertical pen? 3= 105 Angle = 10.5 yuan.
Method 4: 3.5 yuan with vertical pen? 3= 10.5 yuan.
(2) Understand the decimal multiplication of integers and reveal the topic.
1, the comparison shows that
Teacher: The students are great! The above four algorithms, some students put 3.5? 3 is regarded as the result of adding three 3.5, and finally10.5 is obtained; Some students divide the calculation into yuan and angle, first calculate the whole yuan, then calculate the whole angle, and finally add up; Some students use the promotion rate between RMB units and regard 3.5 yuan as 35 angles to calculate the results; Let's look at the fourth method, directly calculate 3.5? 3=, students, what is the difference between this multiplication formula and the multiplication formula you have learned before?
Students will find that there are decimals or decimals multiplied by integers in the formula.
Teacher: This is the question we are going to study today. (blackboard writing: decimal times integer. ) Then how do we calculate this formula? Just now, a classmate said that 3.5 yuan is equal to 35. Let's try to count 3.5 yuan as 35 angles.
3.5 yuan has expanded to 10 times the size? 3. 5 jiao
? 3 ? three
_______________ _______________
1 0.5 yuan reduced to110? 1 0 5 angle
105 Angle is equal to 10.5 yuan.
Step 2 try to solve it
Teacher: We have just worked out how much it costs to buy a kite and three kites from 3.5 yuan. So, students, can you use the same method to calculate just now? If the teacher wants to buy a kite from 4.6 yuan, how to arrange and calculate it?
The students tried to calculate separately.
(3) Calculation method of multiplying decimal by integer
1, try independently
Teacher: The students are so clever that they solved the problem of buying kites at once. Now the teacher will test you (show me the formula 0.72? 5=), 0.72 is not money, what shall we do now?
Blackboard writing: 0.72
? five
_____________
Emphasize vertical calculation by integer multiplication.
① Students think independently.
② Calculation method of group communication.
3 report and demonstrate.
The teacher demonstrates the process of vertical calculus: 0. Is 7 2 times that of 100? 7 2
? 5 ? five
_ _ _ _ _ _ _ _ _ _ reduced to its1100 _? ____________
3.6 0 3 6 0
Teacher: Looking back, we calculated 0.72? How did we work out the process of 5= just now?
Let the students draw the following conclusions: First, expand the first factor of 0.72 to its 100 times to become 72, and the product will also be expanded to 100 times. If the original product is needed, the multiplied product 360 will be reduced to its1100. (Hint: 0 after the decimal point can be removed)
● Note: If there is 0 at the end of the product, point to the decimal point of the product first, and then put? 0? Remove.
2. Summarize the general method of multiplying decimal by integer.
Teacher: Compared with Equation 3.5? 3、0.72? 5. Think about it. When you multiply a decimal by an integer, what do you do first? Do what again? What did you do in the end?
When students tell the process of multiplying decimals by integers in turn, help students sort out the general methods of multiplying decimals by integers:
① Convert decimals into integers first;
② Calculate the product by integer multiplication;
③ Determine the decimal point position of the product.
Third, consolidate the practice.
1, Teacher: The students are very clever. Now the teacher wants to see which one is better at learning and mastering new knowledge. Let's finish Example 2 together? Do it. Problems 1 and 2 in. After that, please discuss: What's the difference between decimal times integer and integer times integer?
(① One factor in multiplying decimal by integer is decimal, and two factors in multiplying integer by integer are integers; (2) In the product of decimal times integer, if there is a 0 at the end of decimal, this 0 can be removed, but the 0 at the end of integer times integer product cannot be removed. )
2. Complete the questions in exercise 1/and 2.
3. After class, use reasonable methods to estimate the distance between your home and school, and complete the exercise 1-3.
Four. abstract
Teacher: Students, time flies. Who can tell me what we learned today? What should I pay attention to when multiplying decimals by integers? Do you find any difference between multiplication and addition and subtraction of decimals?
1, student report
2, the teacher summary evaluation
Design of Teaching Plan for Multiplying Integer by Binary in People' s Education Edition
Teaching content:
(Example of Fractional Multiplication, the fifth edition textbook of People's Education Press 1)
Teaching objectives:
1. Make students understand the arithmetic of decimal multiplication by integer, master the calculation method of decimal multiplication by integer, and do written calculations.
2. Make students experience the process of transforming decimal multiplication into integer multiplication, and experience the mathematical thinking method of transformation.
3. Feel the wide application of fractional multiplication in life.
Teaching emphases and difficulties:
Understand the arithmetic and algorithm of decimal multiplication of integers.
Teaching preparation:
Theme slide
Teaching process:
[Warm-up before class]
2? 3= 5000? 17=
20? 3= 500? 17=
200? 3= 50? 17=
2000? 3= 5? 17=
Give an oral answer and tell me what mathematical laws you have found.
First, situational introduction
1. During the day, several children want to fly kites together in the square. They came to the shop to buy kites. Observe the theme map. What mathematical information did you get from it?
2. Students speak freely (bird and kite 3.5 yuan/only) (the teacher writes on the blackboard with the trend)
If you want to buy a kite, what shape are you going to buy? How many/much? (The teacher writes on the blackboard)
Type unit price quantity
Bird kite 3.5
Fish Kite 6.4
Triangle kite 4.6
Half-circle kite 7.8
If three children want to buy three birds and kites, how much do they have to pay? How to form?
5. Students are independent.
6. exchange ideas 3.5 3 or 3.5+3.5+3.5
7. The teacher summed up the meaning of decimal multiplication by integer and revealed the topic (decimal multiplication by integer).
Second, autonomous computing.
1、3.5? How much is 3? Please try to calculate the figures yourself. (Teachers patrol and ask some students to list different calculation processes on the blackboard. )
2, the whole class to exchange various methods
The teacher pointed out that we should learn the following methods.
4. In the process of students' self-explanation, the teacher writes on the blackboard, and emphatically points out that the key step is to convert 3.5 yuan into 35 angles, which is actually to convert decimals into integers.
Try to work out your math problems like this, what kind of kite to buy, how much to buy and how much to pay.
6. Check at the same table.
Third, explore arithmetic and calculation methods.
1, showing the formula 0.72? 5=? Question:? 0.72 is not money, how to calculate the vertical calculation of independent columns, and name the board.
2. Tell me why? what do you think? (The teacher writes it on the blackboard conveniently)
3, deskmate, talk to each other.
4. Ask students to observe product 3.60 and ask questions:? What is a decimal equal to 3.60 (3.6) Tell the students that after calculating the product, according to the basic properties of the decimal, the 0 at the end of the decimal can be removed.
5. Calculate 3. 15? eight
6. Discuss in groups of four how to calculate decimal times integer.
7. The whole class exchanged and summarized the calculation method of multiplying decimal by integer.
① Convert decimals into integers first;
② Calculate the product by integer multiplication;
③ Determine the decimal point position of the product.
Fourth, practice consolidation.
1, Exercise 1, Questions 2 and 3
Verb (abbreviation of verb) course summary
1. What did you learn from this course?
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