Number where the ones digit is 1, 3, 5, 7 or 9.
- Number that is a multiple of 2 minus one.
- Number in the form (2n + 1) or (2n – 1) where n ∈ \(\mathbb{Z}\).
Examples
- The sequence of odd whole numbers is: {1, 3, 5, 7, 9, 11, 13, …}.
- The set of odd integers is : {…, –7, –5, –3, –1, 1, 3, 5, 7, …}.
- Numbers like 4.5 or -12.9 are not odd numbers, because they are not integers.