State precisely (but concisely) what it means for an integer n to be odd.

Question

What will be an ideal response?

Answer 1

Some acceptable answers:
a. An integer n is odd if, and only if, n = 2k + 1 for some integer k:
b. An integer n is odd if, and only if, n equals 2 times some integer plus 1.
c. An integer n is odd if, and only if, there exists an integer m such that n = 2m + 1 .