31010 − (5000 − 3774) = 31010 − 1226 = 29784
$\begin{array}{r}\begin{array}{r}-\end{array}\underline{\begin{array}{r}5000\\ 3774\end{array}}\\ \begin{array}{r}1226\end{array}\end{array}$
 
$\begin{array}{r}\begin{array}{r}-\end{array}\underline{\begin{array}{r}31010\\ 1226\end{array}}\\ \begin{array}{r}29784\end{array}\end{array}$
 
(4000 − 500 : 100) * 10 = (4000 − 5) * 10 = 3995 * 10 = 39950