If a number is a multiple of 2, it is even and can be expressed as 2n; Otherwise, it is an odd number, which can be expressed as 2n+ 1(n is an integer), that is, the remainder of odd number divided by two is 1.
Extended data:
Regarding even and odd numbers, there are the following properties:
1, two consecutive integers must be odd and even;
2. The sum or difference between odd numbers and odd numbers is even; The sum or difference between even and odd numbers is odd; The sum of any number of even numbers is even; The sum of odd numbers is odd; The sum of even and odd numbers is even;
3. The sum or difference between two odd numbers (even numbers) is even; The sum or difference between even and odd numbers must be odd numbers;
4. All positive even numbers except 2 are composite numbers;
5. The greatest common divisor of adjacent even numbers is 2, and the least common multiple is half of their product;
6. The product of odd number and odd number is odd number; The product of even number and even number is even number; The product of odd number and even number is even number;
7. Even numbers must be 0, 2, 4, 6 or 8; Odd numbers must be 1, 3, 5, 7 or 9;
8. Any odd number is not equal to any even number; The continuous product of several integers, if one of them is even, the product must be even;
9. Even squares divided by 4, odd squares divided by 8, the remainder is 1.
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