Teaching objectives:
1. can read and write more than 100 million numbers correctly according to several levels.
2. In the process of exploring hundreds of millions of digital reading and writing methods, cultivate students' analogical transfer ability.
3. In the real situation, feel the wide application of large numbers in daily life, further experience the application value of mathematics, and cultivate students' interest and goodwill in mathematics.
Teaching focus:
More than 100 million reading and writing methods.
Teaching difficulties:
Read and write numbers with 0.
Teaching preparation:
courseware
Teaching process:
First, review the introduction.
(A) review the old knowledge
1. Read the number of lines drawn below.
Teacher: How do you pronounce numbers within 100 million?
2. Write down the number of lines drawn below.
Teacher: How to write numbers within 100 million?
(B) the introduction of new courses
Teacher: We have learned to read and write numbers within 100 million, but there are not only numbers within 100 million in our lives, but also numbers over 100 million (courseware demonstration). How to read and write such a big number? We will study in this class.
Design intention: review the reading and writing methods of numbers less than 1 100 million according to the specific situation, prepare for learning the reading and writing methods of numbers more than 1 100 million, and let students feel the wide application of large numbers in daily life.
Second, explore new knowledge.
(1) The number of readers exceeds 1 100 million.
1. courseware gives an example.
2. Teacher: Try to read these numbers. (7 billion,104.02 billion, 40.305 billion)
3. Summary
(1) Teacher: Read these numbers again and think about how you read the numbers at each level. (Numbers of 10000 and 1000000 are all read according to the pronunciation of individual levels, and a word "100000" or "100000" is added at the end).
(2) Read the following figures.
(3) Teacher: Each of these three numbers has many zeros. Who has read it and who hasn't?
(4) Teacher: Based on what everyone said, think about how to pronounce the number of more than 100 million.
4. practice: do it.
9200000000 26705000000 508040003000 300700400
Teacher: You can read the numbers in the number sequence table. What if there is no numerical sequence table? (grading)
Teacher: Read these numbers.
Design intention: Let students read by themselves, guide students to consciously transfer the reading method of numbers within 100 million to the reading method of numbers above 100 million in the process of repeated reading, and cultivate students' migration and analogy ability.
(B) the number of hundreds of millions of words
1. Courseware demonstration
300 million? 3,090,703,020,000.
2. Teacher: Try to write these numbers. (300000000、3090000000、700300200000)
Mathematics courseware II for the fourth grade of primary school
Teaching objectives:
Mastering the reading method of two series can correctly read large numbers within 100 million and understand the reading rules.
Practice reading, so that students can understand the connection and difference between ten thousand series reading and one level reading.
Combine reading to cultivate students' analogical and inductive abilities.
Guide students to effectively use their own life experience and existing knowledge level to explore and understand new knowledge.
Cultivate students' observation and hands-on operation ability, cooperation consciousness and inquiry spirit.
Through specific teaching situations, cultivate students' feelings about large numbers and develop their sense of numbers.
Teaching focus:
Two-level pronunciation of numbers.
Teaching difficulties:
The pronunciation of numbers with 0 in the middle and at the end of each level.
Teaching process:
First, create a scenario generation problem.
Read the numbers below.
305300535002879
(1) What numeration units have we learned?
(2) Please say the numbers you have learned in order in the number sequence table.
(3) How many digits are included in the ten thousand categories?
Second, explore communication and solve problems.
Pronunciation of the numbers 1 and 10000.
We have learned how to read numbers within 10,000. And how to read a large number of urban population data like ours yesterday?
(1) Show a number table with two levels, and present 2496 under the corresponding numbers for students to read.
(2) Presenting 24960000 again
Let the students try to read.
Compare the numerical differences between 24960000 and 24960000.
Inspiration: guide the reading of 24960000.
Tell me what the number on each number means, and lead us to say a * * *, how many are there?
What are the characteristics of this number? (the four digits in the first level are all O, that is, these numbers are all integers, and the zeros at the end are not read. What are the similarities and differences between the reading method and the previous number reading method?
Similarity: ten thousand series should be read according to the reading method of one level first.
Difference: the number of 10,000 levels should be followed by the word "10,000".
Summarize the reading method of ten thousand series
Summary: To read the integer of ten thousand, first grade it, then read the number of ten thousand according to the series, and then add a word "ten thousand" after it. Don't read all four zeros of each level.
Practice reading.
50000 180000235000040000000
2. How to read 10,000 and 2-level numbers?
Learn how to read numbers with zeros in the middle.
① blackboard writing 6407000.
② Guide and observe the similarities and differences between 6407000 and 24960000.
③ Students try to read independently and exchange reading methods.
(4) Summary reading method: Grading-reading the numbers on the 10,000-level first-and then reading the numbers on the first level.
Teachers and students describe the blackboard together, 6.407 million.
(1) How to pronounce the number with 0 at the end of the learning level?
Write it on the blackboard.
② Students try to teach themselves to read step by step.
The teacher and the students read together.
④ Summary reading method: those with zeros in the middle of each level should read zeros.
⑤ Teachers and students should read according to the correct reading methods. (blackboard writing: 85 million 3 million. )
Third, consolidate the application of internationalization and improve internationalization.
"Do" on page 5 of the textbook.
(1) Observe the characteristics of each number. Reading at the same table.
2. Do exercises 1, question 2.
The teacher dials the number on the counter and the students read.
Fourth, review, organize, reflect and improve.
Students, what have we learned in this class? What did you get?