For a number (a), the inverse is (1/a) if (a neq 0)
For a fraction (a/b), the inverse is (b/a) if (a neq 0)
For a matrix (A), the inverse is (A^{-1}) such that (AA^{-1} = I)
For a function (f(x)), the inverse (f^{-1}(x)) is found by swapping (x) and (y) and solving for (y)
For a modular inverse of (a mod m), find (x) such that (ax equiv 1 pmod m)
Check that the inverse exists before calculating it