− при делении 66 на 8, получаем 8, а под 66 пишем 64.
$\begin{array}{cc}\begin{array}{l}\underset{¯}{\phantom{0}}661520\\ \phantom{0}\underset{¯}{64}\\ \phantom{0}\underset{¯}{\phantom{0}}21\\ \phantom{00}\underset{¯}{16}\\ \phantom{00}\underset{¯}{\phantom{0}}55\\ \phantom{000}\underset{¯}{48}\\ \phantom{000}\underset{¯}{\phantom{0}}72\\ \phantom{0000}\underset{¯}{72}\\ \phantom{00000}\underset{¯}{\phantom{0}}0\\ \phantom{000000}\underset{¯}{0}\\ \phantom{000000}0\end{array}& \begin{array}{l}\overline{)8}\\ \overline{\overline{)82690}}\end{array}\end{array}$