Irrational numbers are
numbers that cannot be expressed as a ratio of integers in the form of p/q,
where p and q are integers, and q is not equal to zero.
In other words, irrational numbers are numerical values that
are not rational numbers - that is, they do not terminate or repeat as
decimals, and cannot be represented by an integer fraction.
Based on the definition above,
4, which is rational
5.58703... is irrational