An odd number is an integer that is not even. In other words, odd numbers are integers not divisible by $2,$ like the following numbers. All these numbers are not multiples of $2$ and result in a not integer rational number when divided by $2.$

$n$	$\frac{n}{2}$	$\frac{n}{2}=k$	Odd?
$\text{-}5$	$\frac{\text{-}5}{2}$	$\text{-}2.5$	$\text{Yes}$
$\text{-}3$	$\frac{\text{-}3}{2}$	$\text{-}1.5$	$\text{Yes}$
$\text{-}1$	$\frac{\text{-}1}{2}$	$\text{-}0.5$	$\text{Yes}$
$1$	$\frac{1}{2}$	$0.5$	$\text{Yes}$
$3$	$\frac{3}{2}$	$1.5$	$\text{Yes}$
$5$	$\frac{5}{2}$	$2.5$	$\text{Yes}$

Odd numbers are usually defined as all numbers $n$ that can be written in the form $n=2k+1,$ where $k$ is an integer.