\[\boxed{\mathbf{Страница}\mathbf{\ 45}\mathbf{.}\mathbf{\ }Еуроки\ - \ ДЗ\ без\ мороки}\]
\[\boxed{\mathbf{158}\mathbf{.}\mathbf{\ }}\]
\[5 \cdot (4 \cdot 9) = 5 \cdot 4 \cdot 9\]
\[(30 \cdot 2) \cdot 7 = 30 \cdot 2 \cdot 7\]
\[(2 \cdot 4) \cdot (3 \cdot 5) = 2 \cdot 4 \cdot 3 \cdot 5\]
\[\boxed{\mathbf{159}\mathbf{.}\mathbf{\ }}\]
\[14 \cdot 0 \cdot 1 = 0 \cdot 25 \cdot 4\]
\[2 \cdot 2 \cdot 5 \cdot 0 < 4 \cdot 5 \cdot 1\]
\[2 \cdot 3 \cdot 4 = 8 \cdot 3\]
\[5 \cdot 6 \cdot 1 > 1 \cdot 2\]
\[\boxed{\mathbf{160}\mathbf{.}}\]
\[\bigtriangleup \cdot \bigodot = \bigodot \cdot \bigtriangleup\]
\[a \cdot b = b \cdot a\]
\[\boxed{\mathbf{161}\mathbf{.}\mathbf{\ }}\]
\[(t \cdot \ \boxdot ) \cdot \ \bigtriangleup = t \cdot ( \boxdot \ \cdot \ \bigtriangleup )\]
\[(a \cdot b) \cdot c = a \cdot (b \cdot c)\]
\[\boxed{\mathbf{162}\mathbf{.}}\]
\[271 + 129 = 400\]
\[300 - 86 = 214\]
\[\boxed{\mathbf{163}\mathbf{.}}\]
\[8 \cdot 7 = 56\]
\[63\ :9 = 7\]
\[\boxed{\mathbf{164}\mathbf{.}}\]
\[Задумано\ число\ 3.\]
\[3 \cdot 3 = 9\]
\[9 + 40 = 49\]
\[49 - 3 \cdot 3 = 40\]
\[40\ :5 = 8\]
\[Верно.\]