\[\boxed{\mathbf{Вариант\ 2.}}\]
\[\boxed{\mathbf{1.}}\]
\[1)\]
\[2)\ P = 2 \cdot (2 + 4) = 2 \cdot 6 =\]
\[= 12\ см.\]
\[3)\ S = 2 \cdot 4 = 8\ см^{2}.\]
\[\boxed{\mathbf{2.}}\]
\[1)\ Увеличь\ в\ 7\ раз:\]
\[3 \cdot 7 = 21\]
\[7 \cdot 7 = 49\]
\[9 \cdot 7 = 63\]
\[8 \cdot 7 = 56\]
\[6 \cdot 7 = 42\]
\[2)\ Уменьши\ в\ 6\ раз:\]
\[42\ :6 = 7\]
\[36\ :6 = 6\]
\[54\ :6 = 9\]
\[30\ :6 = 5\]
\[48\ :6 = 8\]
\[\boxed{\mathbf{3.}}\]
\[45\ :5 \cdot 6 = 9 \cdot 6 = 54\]
\[56\ :7 \cdot 3 = 8 \cdot 3 = 24\]
\[(40 - 4)\ :9 \cdot 7 = 36\ :9 \cdot 7 =\]
\[= 4 \cdot 7 = 28\]
\[\boxed{\mathbf{4.}}\]
\[13;\ \ 26;\ \ 39.\]