Tính. \[\begin{array}{l}\underline { \times \begin{array}{*{20}{c}}{12}\\{\,3}\end{array}} \\......\end{array}\]

Tính.

\[\begin{array}{l}\underline { \times \begin{array}{*{20}{c}}{12}\\{\,3}\end{array}} \\......\end{array}\]