(3 + 9) * 4 = 48
(9 + 8) * 5 = 85
(6 + 6) * 6 = 72
(8 + 7) * 3 = 45
200 − 1 = 199
400 − 7 = 393
1000 − 100 = 900
1000 − 10 = 990
1000 − 1 = 999
Вычисления:
(3 + 9) * 4 = 3 * 4 + 9 * 4 = 12 + 36 = 48
$\begin{array}{r}\begin{array}{r}+\end{array}\underline{\begin{array}{r}12\\ 36\end{array}}\\ \begin{array}{r}48\end{array}\end{array}$
(9 + 8) * 5 = 9 * 5 + 8 * 5 = 45 + 40 = 85
$\begin{array}{r}\begin{array}{r}+\end{array}\underline{\begin{array}{r}45\\ 40\end{array}}\\ \begin{array}{r}85\end{array}\end{array}$
(6 + 6) * 6 = 6 * 6 + 6 * 6 = 36 + 36 = 72
$\begin{array}{r}\begin{array}{r}+\end{array}\underline{\begin{array}{r}36\\ 36\end{array}}\\ \begin{array}{r}72\end{array}\end{array}$
(8 + 7) * 3 = 8 * 3 + 7 * 3 = 24 + 21 = 45
$\begin{array}{r}\begin{array}{r}+\end{array}\underline{\begin{array}{r}24\\ 21\end{array}}\\ \begin{array}{r}45\end{array}\end{array}$
$\begin{array}{r}\begin{array}{r}-\end{array}\underline{\begin{array}{r}200\\ 1\end{array}}\\ \begin{array}{r}199\end{array}\end{array}$
$\begin{array}{r}\begin{array}{r}-\end{array}\underline{\begin{array}{r}400\\ 7\end{array}}\\ \begin{array}{r}393\end{array}\end{array}$
$\begin{array}{r}\begin{array}{r}-\end{array}\underline{\begin{array}{r}1000\\ 100\end{array}}\\ \begin{array}{r}900\end{array}\end{array}$
$\begin{array}{r}\begin{array}{r}-\end{array}\underline{\begin{array}{r}1000\\ 10\end{array}}\\ \begin{array}{r}990\end{array}\end{array}$
$\begin{array}{r}\begin{array}{r}-\end{array}\underline{\begin{array}{r}1000\\ 1\end{array}}\\ \begin{array}{r}999\end{array}\end{array}$