Read numbers within 100 million.

The arrangement of teaching materials is divided into two levels: the first level is to teach students to read integers of ten thousand, so that students can understand the essence of reading, and the second level is to teach students to read general numbers in two levels and summarize reading.

Write down the number.

Through the lettering information on Yongle Bell in Beijing Dazhong Temple, the activity of writing numbers was induced. Compared with the numerical sequence table, four different numbers appear. The first one gives the writing method by drawing vertical lines, which embodies the idea of marking first and then writing numbers. The other three let students explore and write by themselves.

On this basis, the textbook provides an incomplete text of the rules of writing numbers, with the aim of allowing students to sum up the methods of writing numbers through exchanges and discussions.

Hundreds of millions or more pronunciations.

By presenting the picture that the earth can't bear the population burden, the textbook allows students to understand the global population problem and learn how to read more than 100 million numbers while feeling the big numbers. Compared with the numerical sequence table, the textbook provides more than 300 million numbers, the first one is an integer, and the other two are non-integers. Let the students try to read three levels of numbers from easy to difficult with the help of the number sequence table.

Transfer the reading of numbers within 100 million to the reading of numbers above 100 million. In the summary of reading, pay special attention to guide students to grade first, and then read, with the focus on "0" reading.

How to write hundreds of millions or more?

Combined with the numerical sequence table, the textbook presents 1 integer billion and two non-integer billion, so that students can explore writing methods by thinking, trying, discussing and communicating, and pay attention to guiding students to grade first and then grade writing.

The second question of Do-Do is in the form of exercise group, and several series, tens of thousands of integers and hundreds of millions of integers are arranged in contrast, so that students can further understand the characteristics of graded writing and better master the writing methods.

Rewrite the integer hundred million into a number in units of "hundred million".

The textbook provides three data, the first one presents the result of rewriting, and the other two allow students to complete it independently and be familiar with the rewriting method.

Round off the number of non-integer billions, find the approximate value, and then rewrite it into a number with "100 million" as the unit.

Because I have learned to find the divisor from a non-integer and then rewrite it into a number with the unit of "ten thousand", here I use the form of color blocks and text notes to explain how to omit the mantissa after hundreds of millions of digits by rounding, find its divisor, and then rewrite it directly into a number with the unit of "one hundred million".