The reciprocal of a non-zero number $r$ (usually a real number or rational number, but also a complex number or any non-zero element of a field) is its multiplicative inverse. The reciprocal is usually denoted $r^{-1}$ or $\frac 1r$.

$q$ and $r$ are multiplicative inverses of each other if and only if $r \cdot q = q \cdot r = 1$.

See Also

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