First, refer to different
1, natural number: a number used to measure the number of things or express the order of things, that is, the numbers represented by 0, 1, 2, 3 and 4.
2. Integer: a positive integer, that is, an integer greater than 0, such as 1, 2,3 until n? Negative integers, that is, integers less than 0, such as-1, -2, -3 until -n. (n is a positive integer)
Second, the characteristics are different.
1, natural number: a number representing the number of objects, that is, starting from 0, 0, 1, 2, 3, 4 in turn, forming an infinite group, that is, a non-negative integer.
2. Integer: When n is an integer, even number can be expressed as 2n(n? Is an integer); Odd numbers can be expressed as 2n+ 1 (or 2n- 1). In decimal system, it is judged whether the number is odd or even by looking at the single digits: 1, 3, 5, 7 and 9 are odd; Numbers with digits 0, 2, 4, 6 and 8 are even numbers.
Extended data properties:
1. If the last digit of a number is an even number, the number can be divisible by 2.
2. If the sum of a number is divisible by 3, then this integer can be divisible by 3.
3. If the last two digits of a number are divisible by 4, then the number can be divisible by 4.
If the last digit of a number is 0 or 5, the number can be divisible by 5.
If a number is divisible by 2 and 3, it can be divisible by 6.
6. If one digit of a number is truncated, subtract twice the number from the remaining number. If the difference is a multiple of 7, the original number can be divisible by 7. If the difference is too large or it is difficult to see whether it is a multiple of 7 in mental arithmetic, you need to continue the above-mentioned process of "rounding, multiplication, subtraction and difference test" until you can clearly judge.
7. If the product of a finite number of integers is odd, then every integer is odd; If the product of a finite number of integers is even, at least one of these integers is even; The sum and difference of two integers have the same parity; If the square root of an integer is an integer, then both have the same parity.