\[Страница\ 20.\]
\[\boxed{\mathbf{7.}}\]
\[A \in 59;\ \ \ \]
\[A \in 18;\]
\[B \in 621.\]
\[\boxed{\mathbf{8.}}\]
\[A \in 9\]
\[A \in 27\]
\[A \in 45\]
\[A \in 54\]
\[A \notin 17\]
\[A \notin 41\]
\[\boxed{\mathbf{9.}}\]
\[880\ :20 = 44\]
\[44 + 42 = 86\]
\[6364\ :86 = 74\]
\[6364 - 74 = 6290\]
\[\textbf{б)}\ 548\ 316\ :(41 - 38)^{3} =\]
\[= 548\ 316\ :3^{3} = 548\ 316\ :27 =\]
\[= 20\ 308\]
\[\boxed{\mathbf{10.}}\]
\[A > B\ в\ 6\ раз;\]
\[B < C\ в\ 2\ раза.\]
\[A > C\ в\ 3\ раза.\]