1 is the counting method we often say, and the progress between every two adjacent counting units is ten. There are ten commonly used counting units, such as ten, hundred, thousand, ten thousand, one hundred thousand, one million, ten million, one billion, ten billion, one hundred billion and so on.

2. If the result is greater than 0, the former is greater than the latter, otherwise, the former is less than the latter.

3. Fraction and decimal are actually the same thing. You can divide all decimals into numbers, or you can divide most fractions into decimals. So the basic properties of fractions are the same as decimals.

4. Forward a number, which is 65,438+00 times smaller than the original number, two forward numbers, 65,438+000 times smaller, three small numbers ... a backward number, 65,438+00 times larger, two forward numbers, three forward numbers, 65,438+000 times larger. ......

In addition, I would like to remind you that the meaning of removing the 0 after the decimal point will be different and the size will change!

5。 , prime number, composite number

Prime numbers are also called prime numbers. The number of prime numbers is infinite. Composite number: The divisor of a number has other divisors besides 1 and itself. This number is called a composite number. 2 is not a composite number, 1 is neither a prime number nor a composite number. Prime factors are divisors: factors of a composite number, and these factors are prime numbers.

Multiplication factor

In division, if the dividend is divided by the divisor, the quotient obtained is a natural number, and there is no remainder, it is said that the dividend is a multiple of the dividend, and the divisor is a factor of the dividend.