§ Задание 7
\[\boxed{\mathbf{7}\mathbf{.}}\]

\[\textbf{б)}\ 5 - 6 = 5 = 51\]
\[7 + 4 = 7 = 79\]
\[65 - (11 - 7) = 6 = 61\]
\[42 + (16 - 9) = 4 = 49\]
\[\boxed{\mathbf{7}\mathbf{.}}\]

\[\textbf{б)}\ 5 - 6 = 5 = 51\]
\[7 + 4 = 7 = 79\]
\[65 - (11 - 7) = 6 = 61\]
\[42 + (16 - 9) = 4 = 49\]