What is a negative rational number?

Answer 1

Minus two.
Some rational numbers are positive, some are negative. -9 is a negative rational number.

Answer 2

Any negative number that can be written as a fraction is rational. For example,

-1 and -1/2 are both rational, but negative Pi isn't.

Answer 3

It is any number that can be expressed in the form a/b where a is a negative integer and b is a positive integer.