All numbers that cannot be divided exactly by 2 are odd numbers.
Odd numbers can't be divided evenly into groups of two. The number five can be divided into two groups of two and one group of one. Odd numbers always end with a digit of 1, 3, 5, 7, or 9.
About Number 9. Nine is the smallest odd composite number and the minimum composite odd number that is no Fermat pseudoprime. It is the smallest natural number n, for each non-negative integer can be represented as a sum of at most n positive cubes (see Waring's problem), and the smallest positive integer n for which n squares in pairs of different positive edge length exist, the can be put together to form a rectangle. Number Nine is the number which (other than 0) as a single digit checksum generally occurs (in decimal number system) after multiplication by an arbitrary integer always even, and the number which is added to any other (except 0 and -9), as a single digit checksum the same result as the starting number itself - ie it behaves quasi-neutral.
About Number 3. Three is the first odd prime number and the second smallest right after number two. At the same time it is the first Mersenne prime (2 ^ 2-1), the first Fermat prime (2 ^ {2 ^ 0} +1), the second Sophie Germain prime and the second Mersenne prime exponent. It is the fourth number of the Fibonacci sequence and the second one that is unique. The triangle is the simplest geometric figure in the plane. With the calculation of its sizes deals trigonometry. Rule of three: If the sum of the digits of a number is a multiple of three, the underlying number is divisible by three.
What Is An Odd Number?
An odd number is an integer which is not a multiple of two. If it is divided by two the result is a fraction. One is the first odd positive number. The next four bigger odd numbers are three, five, seven, and nine. An integer that is not an odd number is an even number.
An even number is defined as a whole number that is a multiple of two. If an even number is divided by two, the result is another whole number. On the other hand, an odd number, when divided by two, will result in a fraction. Since odd and even numbers are defined only in reference to the set of integers (..., -3, -2, -1, 0, 1, 2, 3, ...), all negative numbers can also be either odd or even.