Rewrite the the statement " $If\: a\:natural\:number\:is\:odd,\: then\:its\:square\:is\:also\:odd."$ in five different ways conveying the same meaning.

The given statement is
$"If\: a\:natural\:number\:is\:odd,\: then\:its\:square\:is\:also\:odd."$
Five different statements conveying the same meaning are
1. A natural number is odd only if its square is odd.
2. A natural number is odd implies that its square is odd.
3. If the square of a natural number is not odd then the number is also not odd.
4. For the square of a natural number to be odd it is sufficient that the number is odd.
5. For a natural number to be odd it is necessary that its square is off