Đặt tính rồi tính. a) 48 : 4 55 : 5 42 : 2

 Em đặt tính rồi thực hiện phép chia từ trái sang phải.

a)          $\begin{array}{l}\begin{array}{c}48\\ \underset{¯}{4}\end{array}\begin{array}{c}4\\ 12\end{array}\\ 08\\ \underset{¯}{8}\\ 0\end{array}$                                   $\begin{array}{l}\begin{array}{c}55\\ \underset{¯}{5}\end{array}\begin{array}{c}5\\ 11\end{array}\\ 05\\ \underset{¯}{5}\\ 0\end{array}$                                     $\begin{array}{l}\begin{array}{c}42\\ \underset{¯}{4}\end{array}\begin{array}{c}2\\ 21\end{array}\\ 02\\ \underset{¯}{2}\\ 0\end{array}$             

48 : 4 = 12                                       55 : 5 = 11                                     42 : 2 = 21