Answer
$8.94$
Work Step by Step
Subtraction the first to numbers::
\begin{array}{ccc}
\require{cancel}
& & &2\space ^{13}\space^{11}
\\&&&\cancel{3}\cancel{4}.\cancel{1}4
\\&- & &\underline{08.70}
\\&&&25.44
\end{array}
Subtract $16.5$ to the result to obtain:
\begin{array}{ccc}
\require{cancel}
& & &1\space ^{14}\space^{14}
\\&&&\cancel{2}\cancel{5}.\cancel{4}4
\\&- & &\underline{16.50}
\\&&&08.94
\end{array}
