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. The forward rate between two adjacent counting units is "ten", which is called decimal counting method. Special attention: the difference between counting units and numbers.
2. When using numbers to represent numbers, these counting units should be arranged in a certain order, and their positions are called numbers.
3. 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.
More than 100 million reading methods are graded first, starting from the high position. Read level 100 million, then level 10,000, and finally level 1. The number of billion should be read according to the pronunciation of the number of billion, and then the word "billion" should be added after it.
Ten thousand series should be read according to the reading method of ten thousand series, and then the word "ten thousand" should be added after it. No matter how many zeros there are at the end of each stage, they will not be read. Other numbers have a "0" or several "0" in succession, all of which are read only.
6, hundreds of millions of figures are written from the top, first write 100 million, then write 10 thousand, and finally write one level. There is no unit on any number, just write 0 on that number.
7. The size of the comparison number is determined by two numbers with different digits, and the more digits, the greater the number. Two numbers with the same number of digits are compared from most significant bit.
8. Find the divisor, and the mantissa after omitting ten thousand digits depends on the number on one thousand digits; The mantissa after omitting 1 100 million bits depends on the number on1100 million bits.
This method of finding the divisor is called "rounding". Whether it is "rounding" or "decimal" depends on whether the number in the most significant digit of the omitted mantissa is less than 5 or equal to or greater than 5. If less than 5, the mantissa will be discarded; If it is equal to or greater than 5, advance to 1 and then discard the mantissa.
9. The number of objects: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, ... are all natural numbers. There is no object, which is represented by 0, and 0 is also a natural number. All natural numbers are integers.
10, the smallest natural number is 0, there is no largest natural number, and the number of natural numbers is infinite.
1 1, and the ratio between every two adjacent counting units is ten. This counting method is called decimal counting method.