What inequalities and intervals are? If it is given that a real number 'p' is not less than another real number 'q', we understand that either p should be equal to q or p should be greater than q. We express the same as p = q or p > q or p ≥ q. If p is greater than q, then, is not p - q a positive number? It is. Statements like p < q or p > q are called inequalities. We employ the concept of inequalities to understand sets referred to as intervals. We define an interval as a range of values from which the real number "p" is likely to assume values. In this context, interval is more restricted as compared to a set of real numbers which ranges from + ∞  to - ∞ . We should note that ' ∞ ' is not a real number and it is employed only because of convenience.