Условие:

Вычисли устно.
600 − 200
24 + 300
970 − 70
360 + 36
9 * 7
42 : 6
6 * 8
25 : 5
20 + (8 * 2)
24 : (72 − 66)
(9 * 9) − (18 + 62)
(64 − 57) * 7

600 − 200 = 400
24 + 300 = 324
970 − 70 = 900
360 + 36 = 396
9 * 7 = 63
42 : 6 = 7
6 * 8 = 48
25 : 5 = 5
20 + (8 * 2) = 36
24 : (72 − 66) = 4
(9 * 9) − (18 + 62) = 1
(64 − 57) * 7 = 49
Вычисления:
600 − 200 = 400
$\begin{array}{r}\begin{array}{r}-\end{array}\underline{\begin{array}{r}600\\ 200\end{array}}\\ \begin{array}{r}400\end{array}\end{array}$
24 + 300 = 324
$\begin{array}{r}\begin{array}{r}+\end{array}\underline{\begin{array}{r}24\\ 300\end{array}}\\ \begin{array}{r}324\end{array}\end{array}$
970 − 70 = 900
$\begin{array}{r}\begin{array}{r}-\end{array}\underline{\begin{array}{r}970\\ 70\end{array}}\\ \begin{array}{r}900\end{array}\end{array}$
360 + 36 = 396
$\begin{array}{r}\begin{array}{r}+\end{array}\underline{\begin{array}{r}360\\ 36\end{array}}\\ \begin{array}{r}396\end{array}\end{array}$
9 * 7 = 63
42 : 6 = 7
6 * 8 = 48
25 : 5 = 5
20 + (8 * 2) = 20 + 16 = 36
$\begin{array}{r}\begin{array}{r}+\end{array}\underline{\begin{array}{r}20\\ 16\end{array}}\\ \begin{array}{r}36\end{array}\end{array}$
24 : (72 − 66) = 24 : 6 = 4
$\begin{array}{r}\begin{array}{r}-\end{array}\underline{\begin{array}{r}72\\ 66\end{array}}\\ \begin{array}{r}6\end{array}\end{array}$
(9 * 9) − (18 + 62) = 81 − 80 = 1
$\begin{array}{r}\begin{array}{r}+\end{array}\underline{\begin{array}{r}18\\ 62\end{array}}\\ \begin{array}{r}80\end{array}\end{array}$
$\begin{array}{r}\begin{array}{r}-\end{array}\underline{\begin{array}{r}81\\ 80\end{array}}\\ \begin{array}{r}1\end{array}\end{array}$
(64 − 57) * 7 = 7 * 7 = 49
$\begin{array}{r}\begin{array}{r}-\end{array}\underline{\begin{array}{r}64\\ 57\end{array}}\\ \begin{array}{r}7\end{array}\end{array}$