An odd number is an integer that cannot be evenly divided by 2. This means that when you divide an odd number by 2, there will always be a remainder of 1. Examples of odd numbers include 1, 3, 5, 7, and 9. Odd numbers can be both positive and negative, such as -1 and -3. Odd numbers are part of the broader category of integers, which also includes even numbers. Even numbers are those that can be divided by 2 without a remainder, like 2, 4, and 6. Together, odd and even numbers make up the set of whole numbers used in everyday counting and mathematics.