Вычисления:
72 : 8 = 9
68 − 68 = 0
$\begin{array}{r}\begin{array}{r}-\end{array}\underline{\begin{array}{r}68\\ 68\end{array}}\\ \begin{array}{r}0\end{array}\end{array}$
39 + 7 = 46
$\begin{array}{r}\begin{array}{r}+\end{array}\underline{\begin{array}{r}39\\ 7\end{array}}\\ \begin{array}{r}46\end{array}\end{array}$
63 : 7 = 9
1 * 9 = 9
48 − 9 = 39
$\begin{array}{r}\begin{array}{r}-\end{array}\underline{\begin{array}{r}48\\ 9\end{array}}\\ \begin{array}{r}39\end{array}\end{array}$
6 * 1 = 6
0 : 8 = 0
61 − 8 = 53
$\begin{array}{r}\begin{array}{r}-\end{array}\underline{\begin{array}{r}61\\ 8\end{array}}\\ \begin{array}{r}53\end{array}\end{array}$
54 − 0 = 54
0 + 99 = 99
33 − 5 = 28
$\begin{array}{r}\begin{array}{r}-\end{array}\underline{\begin{array}{r}33\\ 5\end{array}}\\ \begin{array}{r}28\end{array}\end{array}$