Odd integer

An odd integer $n$ is an integer which is not a multiple of 2. Every odd integer can be written in the form $2k + 1$ for some unique other integer $k$ . The odd integers with smallest absolute value are $1, -1, 3, -3, 5, -5, \ldots$ . The product of any two odd integers is odd, but the sum and difference of any two odd integers are even.