\begin{definition}[Definition:Decimal Expansion/Decimal Place]
Let $x \in \R$ be a real number.
Let the '''decimal expansion''' of $x$ be:
:$x = \sqbrk {s \cdotp d_1 d_2 d_3 \ldots}_{10}$
Then $d_k$ is defined as being the digit in the $k$th '''decimal place'''.
\end{definition}