\begin{enumerate}
    \item $b:$ \quad Bob wins the lottery. \\
          $n:$ \quad Bob gets all the numbers right.
          $$ b \biimp n$$
    \item $S:$ \quad Mozart was born in Salzburg. \\
          $I:$ \quad Mozart was born in Innsbruck
          $$ S \land \neg I $$
    \item $l:$ \quad The year is a leap-year. \\
          $f:$ \quad Februar has 29 days.
          $$ l \imp f $$
\end{enumerate}