1. Rewrite the following statement with “if-then” in five different ways conveying the same meaning.
If a natural number is odd, then its square is also odd.
a.) If the square of a natural number is odd, then the natural number is odd.
b.) A natural number is not odd only if its square is not odd.
c.) For a natural number to be odd it is necessary that its square is odd.
d.) For the square of a natural number to be odd, it is sufficient that the number is odd
e.) If the square of a natural number is not odd, then the natural number is not odd.