9 * 7 − 28 = 35
7 * 7 − 28 = 21
5 * 7 − 28 = 7
Вычисления:
9 * 7 − 28 = 63 − 28 = 35
$\begin{array}{r}\begin{array}{r}-\end{array}\underline{\begin{array}{r}63\\ 28\end{array}}\\ \begin{array}{r}35\end{array}\end{array}$
7 * 7 − 28 = 49 − 28 = 21
$\begin{array}{r}\begin{array}{r}-\end{array}\underline{\begin{array}{r}49\\ 28\end{array}}\\ \begin{array}{r}21\end{array}\end{array}$
5 * 7 − 28 = 35 − 28 = 7
$\begin{array}{r}\begin{array}{r}-\end{array}\underline{\begin{array}{r}35\\ 28\end{array}}\\ \begin{array}{r}7\end{array}\end{array}$