\( \begin{array}{c} 456 \\ +237 \\ \hline 693 \end{array} \)
\( \begin{array}{c} 318 \\ +424 \\ \hline 742 \end{array} \)
\( \begin{array}{c} 685 \\ +273 \\ \hline 958 \end{array} \)
\( \begin{array}{c} 445 \\ -227 \\ \hline 218 \end{array} \)
\( \begin{array}{c} 684 \\ -159 \\ \hline 525 \end{array} \)
\( \begin{array}{c} 749 \\ -268 \\ \hline 481 \end{array} \)