(1). The advance rate between every two adjacent counting units is 10. This counting method is called decimal counting method.

(2). For example, 10 10 million is 100 million, and 10 million is101 million.

(3) Number of digits: unit, ten, hundred, thousand, ten thousand, one hundred thousand, one million, ten million, one billion, one billion.

(4) Counting units: one, ten, one hundred, one thousand, ten thousand, one hundred thousand, one million, ten million, one billion, one billion.

(5) How many "ones" does the series represent? How many tens of thousands of numbers represent tens of thousands. How many "billions" do billions of numbers represent?

(6). Every four digits are one level. Divided into: grade, grade, grade.

2. Reading method of numbers: start from the high places, read them level by level, read the numbers of 100 million or 10,000 levels according to the reading method of level by level, and then add a "billion" at the back.

Word or "ten thousand" word. There is a zero in the middle of the number or several consecutive zeros, all of which are read-only. No matter how many zeros are at the end of each level, they are not read.

3. How to write numbers: first write 100 million levels, then write 10,000 levels, and finally write one level. Whoever doesn't have the previous unit will write 0 as a placeholder.

4. Composition of numbers: 308 4000 0860 consists of three tens, eight hundreds, four tens, eight hundreds and six tens; It can also be said that it is composed of 30.8 billion yuan, 40 million yuan and 860 yuan.

5. Find the divisor by "rounding" method: whether to stay or advance depends on omitting the highest digit of the mantissa. If it is 4, 3, 2, 1, 0, it will be omitted; It's 5, 6, 7, 8, 9. Remove the mantissa and go forward 1. For example: 9420000000000 ≈ 94000000 or 9.4 billion (mantissa after omitting 1 100 million bits) When omitting the mantissa after 1 100 million bits, you should see millions of bits. 7508000≈75 10000 or 75 10000 (mantissa after omitting ten thousand digits) When omitting the mantissa after ten thousand digits, you should see thousands.

6. The comparison number has different digits, and the number with more digits is larger; If the number of digits is the same, the largest number from the left is larger. If the first number from the left is the same, compare the second number from the left.

7. Generation of numbers representing the number of objects 1, 2, 3, 4, 5, 6, 7, 8, 9, 10,1are all natural numbers. There is no object, which is represented by 0. 0 is also a natural number. The smallest natural number is 0. There is no maximum natural number, and the number of natural numbers is infinite.

8. Digital rewriting

(1). Rewrite it into a number with "ten thousand" as the unit: it is an integer, with the four zeros at the end removed and the word "ten thousand" added.

(2) Rewrite it into a number with the unit of "100 million": it is an integer. Remove the eight zeros at the end and add a word "100 million".

9. Understand computing tools

(1). As early as 14, China invented the abacus, which has been used ever since.

(2) Each upper bead on the abacus represents 5, and each lower bead represents 1.