The set of rational numbers is an extension of the set of integers. The set formed by positive rational numbers, negative rational numbers, and zero is a new set that we call **set of rational numbers**, represented by **Q**.

Examples:

Notice the picture:

The set of Q is an extension of the set Z.

## Other subsets of Q:

Q

^{*}is the set of nonzero rational numbers;Q

_{+}is the set of positive rational numbers and zero;Q

_{-}is the set of negative rational numbers and zero;Q

_{+}^{*}is the set of rational and positive numbers;Q

_{-}^{*}is the set of negative rational numbers.