80000 + 3789 : 3 = 80000 + 1263 = 81263
1) $\begin{array}{cc}\begin{array}{l}\underset{¯}{\phantom{0}}3789\\ \phantom{0}\underset{¯}{3}\\ \phantom{0}\underset{¯}{\phantom{0}}7\\ \phantom{00}\underset{¯}{6}\\ \phantom{0}\underset{¯}{\phantom{0}}18\\ \phantom{00}\underset{¯}{18}\\ \phantom{000}\underset{¯}{\phantom{0}}9\\ \phantom{0000}\underset{¯}{9}\\ \phantom{0000}0\end{array}& \begin{array}{l}\overline{)3}\\ \overline{\overline{)1263}}\end{array}\end{array}$;
2) 80000 + 1263 = 81263.
 
930 * 86 + 3468 : 34 = 79980 + 102 = 80082
1) $\begin{array}{r}\times \underset{¯}{\begin{array}{r}930\\ 86\end{array}}\\ 5580\\ 7440\phantom{0}\\ \overline{79980}\end{array}$;
2) $\begin{array}{cc}\begin{array}{l}\underset{¯}{\phantom{0}}3468\\ \phantom{0}\underset{¯}{34}\\ \phantom{00}\underset{¯}{\phantom{0}}6\\ \phantom{000}\underset{¯}{0}\\ \phantom{00}\underset{¯}{\phantom{0}}68\\ \phantom{000}\underset{¯}{68}\\ \phantom{0000}0\end{array}& \begin{array}{l}\overline{)34}\\ \overline{\overline{)102}}\end{array}\end{array}$;
3) $\begin{array}{r}\begin{array}{r}+\end{array}\underline{\begin{array}{r}79980\\ 102\end{array}}\\ \begin{array}{r}80082\end{array}\end{array}$.
 
43 км − 3 км 600 м * 8 = 43 км − 28 км 800 м = 14 км 200 м