\newfillinproblem{
\FPsetpar{a}{12}{15}
\FPsetpar{b}{13}{15}
\FPsetpar{c}{2}{4}
\FPsetpar{k}{4}{5}
\item \PTs{1}
  $a=\a$, $b=\b$, $c=\c$, $k=\k$

Evaluate   with two exact decimals

$$ \b:\k= \fillin[b]{3cm}{ \FPsv[2]{b/k}}$$
 }


\newfillinproblem{
\FPsetpar{a}{12}{15}
\FPsetpar{b}{13}{15}
\FPsetpar{c}{2}{4}
\FPsetpar{k}{4}{5}
\item \PTs{1}
  $a=\a$, $b=\b$, $c=\c$, $k=\k$

Evaluate   with two exact decimals

$$ \a:\c= \fillin[b]{3cm}{ \FPsv[2]{a/c}}$$ }