The first volume of fourth-grade mathematics of People's Education Press Unit 1, the list of counting units and number sequences within 100 million, mainly teaches students to further understand the counting units of ten thousand, one hundred thousand, one million, ten million and one hundred million, and then analogize the relationship between every two adjacent counting units, so as to know the number and grade.

At the same time, in the process of learning the relationship between counting units, we should master the numerical sequence table, understand the concept of numerical values and master the reading methods. In this process, not only the students' self-study ability is cultivated, but also their reasoning ability is improved.

1, 10 ten thousand is one hundred thousand, 10 ten thousand is one million, 10 one million is ten million, 10 ten million is one hundred million.

One, ten, one hundred, one thousand and one million are all counting units.

3. When numbers are used to represent numbers, these counting units should be arranged in a certain order, and their positions are called numbers.

4. Number of digits: A number contains several digits, that is, several digits. For example, 652 100 is a six-digit number.

According to our country's counting habit, every four digits are counted from the right.

To understand large numbers, we should first divide all the numbers into three levels, ten thousand levels and one level from the numerical sequence table. From right to left, it is one, ten, one hundred, one thousand, ten thousand, one hundred thousand, ten million, one billion, ten billion, one hundred billion and so on. Secondly, the relationship between all levels in a large number and the rate of series between adjacent two digits are all ten.