How to judge odd and even numbers?

Among the integers, 1, 3, 5, 7 and 9 are odd numbers; Numbers with digits 0, 2, 4, 6 and 8 are even numbers.

In other words, odd numbers are not divisible by 2.

Even numbers are multiples of 2.

Properties of odd and even numbers

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.