Условие:

Какие числа надо записать в окошках, чтобы записи были верными?
707 + _ = 990
502 − _ = 115
_ + 36 = 236
_ − 199 = 256

707 + 283 = 990
502 − 387 = 115
200 + 36 = 236
455 − 199 = 256
Вычисления:
707 + 283= 990
$\begin{array}{r}\begin{array}{r}+\end{array}\underline{\begin{array}{r}707\\ 283\end{array}}\\ \begin{array}{r}990\end{array}\end{array}$
990 − 707 = 283
$\begin{array}{r}\begin{array}{r}-\end{array}\underline{\begin{array}{r}990\\ 707\end{array}}\\ \begin{array}{r}283\end{array}\end{array}$
502 − 387= 115
$\begin{array}{r}\begin{array}{r}-\end{array}\underline{\begin{array}{r}502\\ 387\end{array}}\\ \begin{array}{r}115\end{array}\end{array}$
502 − 115 = 387
$\begin{array}{r}\begin{array}{r}-\end{array}\underline{\begin{array}{r}502\\ 115\end{array}}\\ \begin{array}{r}387\end{array}\end{array}$
200 + 36 = 236
$\begin{array}{r}\begin{array}{r}+\end{array}\underline{\begin{array}{r}200\\ 36\end{array}}\\ \begin{array}{r}236\end{array}\end{array}$
236 − 36 = 200
$\begin{array}{r}\begin{array}{r}-\end{array}\underline{\begin{array}{r}236\\ 36\end{array}}\\ \begin{array}{r}300\end{array}\end{array}$
455 − 199 = 256
$\begin{array}{r}\begin{array}{r}-\end{array}\underline{\begin{array}{r}455\\ 199\end{array}}\\ \begin{array}{r}256\end{array}\end{array}$
256 + 199 = 455
$\begin{array}{r}\begin{array}{r}+\end{array}\underline{\begin{array}{r}256\\ 199\end{array}}\\ \begin{array}{r}455\end{array}\end{array}$