94 * 19 = 1786
$\begin{array}{r}\times \underset{¯}{\begin{array}{r}94\\ 19\end{array}}\\ 846\\ 94\phantom{0}\\ \overline{1786}\end{array}$
 
6842 − 476 + 938 = 6366 + 938 = 7304
1) $\begin{array}{r}\begin{array}{r}-\end{array}\underline{\begin{array}{r}6842\\ 476\end{array}}\\ \begin{array}{r}6366\end{array}\end{array}$;
2) $\begin{array}{r}\begin{array}{r}+\end{array}\underline{\begin{array}{r}6366\\ 938\end{array}}\\ \begin{array}{r}7304\end{array}\end{array}$.
 
58 * 90 : 30 = 5220 : 30 = 174
1) $\begin{array}{r}\times \underset{¯}{\begin{array}{r}58\\ 90\end{array}}\\ 0\\ 522\phantom{0}\\ \overline{5220}\end{array}$;
2) $\begin{array}{cc}\begin{array}{l}\underset{¯}{\phantom{0}}5220\\ \phantom{0}\underset{¯}{30}\\ \underset{¯}{\phantom{0}}222\\ \phantom{0}\underset{¯}{210}\\ \phantom{0}\underset{¯}{\phantom{0}}120\\ \phantom{00}\underset{¯}{120}\\ \phantom{0000}0\end{array}& \begin{array}{l}\overline{)30}\\ \overline{\overline{)174}}\end{array}\end{array}$.