1. The symbol \equiv is used in mathematics to denote equivalence or congruence. 2. It often means that two expressions are identically equal or congruent modulo some number. 3. For example, in modular arithmetic, $a \equiv b \pmod{n}$ means that $a$ and $b$ have the same remainder when divided by $n$. 4. This is a fundamental concept in number theory and algebra used to simplify problems involving divisibility. 5. There is no calculation here, just an explanation of what the symbol \equiv represents.