\begin{definition}[Definition:Digit]
Let $n$ be a number expressed in a particular number base, $b$ for example.
Then $n$ can be expressed as:
:$\sqbrk {r_m r_{m - 1} \ldots r_2 r_1 r_0 . r_{-1} r_{-2} \ldots}_b$
where:
:$m$ is such that $b^m \le n < b^{m+1}$;
:all the $r_i$ are such that $0 \le r_i < b$.
Each of the $r_i$ are known as the '''digits of $n$ (base $b$)'''.
\end{definition}