Numbers which can be written in the form of `p/q` where p and q are integers and q≠0 are called RATIONAL NUMBERS.
All Natural Numbers, i.e. 1, 2, 3, 4, 5, . . . . can be written in the form of `p/q`, where, q≠0. Thus, all Natural Numbers are Rational Number.
All Whole Numbers, i.e. 0, 1, 2, 3, 4, . . . . can be written in the form of `p/q`, where, q≠0. Thus, every Whole Numbers is a Rational Number.
All Integers can be written in the form of `p/q` where, q≠0. Thus, all Integers are Rational Number.
When it is said that, `p/q` is a rational number, or when `p/q` is represented on the number line, it is assumed that q≠0 and p and q have no common factors other than 1. This, means p and q are co-prime. So on the Number Line, among the infinitely many fractions equivalent to `1/2`, but we will choose `1/2` to represent all of them . . .