Tính:

\[\begin{array}{l} \times \begin{array}{*{20}{c}}{31}\\{\underline {\,\,\,3} }\end{array}\\\,\,\,\,....\\\,\,\,\,\,\,\end{array}\]

\[\begin{array}{l} \times \begin{array}{*{20}{c}}{43}\\{\underline {\,\,\,2} }\end{array}\\\,\,\,\,....\\\,\,\,\,\,\,\end{array}\]

\[\begin{array}{l} \times \begin{array}{*{20}{c}}{12}\\{\underline {\,\,\,4} }\end{array}\\\,\,\,\,....\\\,\,\,\,\,\,\end{array}\]

\[\begin{array}{l} \times \begin{array}{*{20}{c}}{11}\\{\underline {\,\,\,8} }\end{array}\\\,\,\,\,....\\\,\,\,\,\,\,\end{array}\]