\[\boxed{\mathbf{Вариант\ 2.}}\]
\[\boxed{\mathbf{1.}}\]
\[1)\ Увеличь\ в\ 3\ раза:\]
\[7 \cdot 3 = 21\]
\[5 \cdot 3 = 15\]
\[8 \cdot 3 = 24\]
\[6 \cdot 3 = 18\]
\[9 \cdot 3 = 27\]
\[2)\ Уменьши\ в\ 4\ раза:\]
\[28\ :4 = 7\]
\[20\ :4 = 5\]
\[32\ :4 = 8\]
\[16\ :4 = 4\]
\[36\ :4 = 9\]
\[\boxed{\mathbf{2.}}\]
\[1)\ \rightarrow \ 9 - 3 = 6.\]
\[2)\ \rightarrow \ 9\ :3 = 3.\]
\[3)\ \rightarrow \ 9 \cdot 3 = 27.\]
\[\boxed{\mathbf{3.}}\]
\[24\ :3 - 3 = 5\]
\[4 \cdot 5 + 3 = 23\]