21 : (63 : (207 − 198)) = 3
468 + 254 − 5 * (28 + 106) = 52
Вычисления:
21 : (63 : (207 − 198)) = 3
1)
$\begin{array}{r}\begin{array}{r}-\end{array}\underline{\begin{array}{r}207\\ 198\end{array}}\\ \begin{array}{r}9\end{array}\end{array}$
2) 63 : 9 = 7
3) 21 : 7 = 3
468 + 254 − 5 * (28 + 106) = 52
1)
$\begin{array}{r}\begin{array}{r}+\end{array}\underline{\begin{array}{r}28\\ 106\end{array}}\\ \begin{array}{r}134\end{array}\end{array}$
2) 5 * 134 = 134 * 5 = 670

3)
$\begin{array}{r}\begin{array}{r}+\end{array}\underline{\begin{array}{r}468\\ 254\end{array}}\\ \begin{array}{r}722\end{array}\end{array}$
4)
$\begin{array}{r}\begin{array}{r}-\end{array}\underline{\begin{array}{r}722\\ 670\end{array}}\\ \begin{array}{r}52\end{array}\end{array}$