(100 − 50) − 20 = 30
60 + (40 − 10) = 90
(45 + 5) + 5 = 55
(93 − 23) − 32 = 38
(30 + 8) − 20​​​​​​​ = 18
(67 − 17) − 7 = 43
100 − (56 + 44) = 0
49 + (99 − 50) = 98
Вычисления:
(100 − 50) − 20 = 50 − 20 = 30
$\begin{array}{r}\begin{array}{r}-\end{array}\underline{\begin{array}{r}100\\ 50\end{array}}\\ \begin{array}{r}50\end{array}\end{array}$
$\begin{array}{r}\begin{array}{r}-\end{array}\underline{\begin{array}{r}50\\ 20\end{array}}\\ \begin{array}{r}30\end{array}\end{array}$
60 + (40 − 10) = 60 + 30 = 90
$\begin{array}{r}\begin{array}{r}-\end{array}\underline{\begin{array}{r}40\\ 10\end{array}}\\ \begin{array}{r}30\end{array}\end{array}$
$\begin{array}{r}\begin{array}{r}+\end{array}\underline{\begin{array}{r}60\\ 30\end{array}}\\ \begin{array}{r}90\end{array}\end{array}$
(45 + 5) + 5 = 50 + 5 = 55
$\begin{array}{r}\begin{array}{r}+\end{array}\underline{\begin{array}{r}45\\ 5\end{array}}\\ \begin{array}{r}50\end{array}\end{array}$
$\begin{array}{r}\begin{array}{r}+\end{array}\underline{\begin{array}{r}50\\ 5\end{array}}\\ \begin{array}{r}55\end{array}\end{array}$
(93 − 23) − 32 = 70 − 32 = 38
$\begin{array}{r}\begin{array}{r}-\end{array}\underline{\begin{array}{r}93\\ 23\end{array}}\\ \begin{array}{r}70\end{array}\end{array}$
$\begin{array}{r}\begin{array}{r}-\end{array}\underline{\begin{array}{r}70\\ 32\end{array}}\\ \begin{array}{r}38\end{array}\end{array}$
(30 + 8) − 20​​​​​​​ = 38 − 20 = 18
$\begin{array}{r}\begin{array}{r}+\end{array}\underline{\begin{array}{r}30\\ 8\end{array}}\\ \begin{array}{r}38\end{array}\end{array}$
$\begin{array}{r}\begin{array}{r}-\end{array}\underline{\begin{array}{r}38\\ 20\end{array}}\\ \begin{array}{r}18\end{array}\end{array}$
(67 − 17) − 7​​​​​​​ = 50 − 7 = 43
$\begin{array}{r}\begin{array}{r}-\end{array}\underline{\begin{array}{r}67\\ 17\end{array}}\\ \begin{array}{r}50\end{array}\end{array}$
$\begin{array}{r}\begin{array}{r}-\end{array}\underline{\begin{array}{r}50\\ 7\end{array}}\\ \begin{array}{r}43\end{array}\end{array}$
100 − (56 + 44) = 100 − 100 = 0
$\begin{array}{r}\begin{array}{r}+\end{array}\underline{\begin{array}{r}56\\ 44\end{array}}\\ \begin{array}{r}100\end{array}\end{array}$
$\begin{array}{r}\begin{array}{r}-\end{array}\underline{\begin{array}{r}100\\ 100\end{array}}\\ \begin{array}{r}0\end{array}\end{array}$
49 + (99 − 50) = 49 + 49 = 98
$\begin{array}{r}\begin{array}{r}-\end{array}\underline{\begin{array}{r}99\\ 50\end{array}}\\ \begin{array}{r}49\end{array}\end{array}$
$\begin{array}{r}\begin{array}{r}+\end{array}\underline{\begin{array}{r}49\\ 49\end{array}}\\ \begin{array}{r}90\end{array}\end{array}$