\begin{definition}[Definition:Anomalous Cancellation]
Let $r = \dfrac a b$ be a fraction where $a$ and $b$ are integers expressed in conventional decimal notation.
'''Anomalous cancellation''' is a phenomenon whereby deleting (that is, cancelling) common digits from the numerator $a$ and the denominator $b$ of $r$, the value of $r$ the fraction does not change.
\end{definition}