\[\boxed{\mathbf{Вариант\ 1.}}\]
\[\boxed{\mathbf{1.}}\]
\[8400\ :12 = 700\]
\[Ответ:в\ 700\ раз.\]
\[\boxed{\mathbf{2.}}\]
\[5600\ :14 = 400\]
\[Ответ:в\ 400\ раз.\]
\[\boxed{\mathbf{3.}}\]
\[\boxed{\mathbf{4.}}\]
\[x \cdot 12 = 1000 - 280\]
\[x \cdot 12 = 720\]
\[x = 720\ :12\]
\[x = 60\]
\[Ответ:x = 60.\]
\[\boxed{\mathbf{5.}}\]
\[40\ 000\ :10 = 400 \cdot 10\]
\[4000 = 4000\]
\[Ответ:число\ 10.\]
\[\boxed{\mathbf{6.}}\]
\[Ответ:160 \cdot (40 \cdot 2).\]
\[\boxed{\mathbf{7.}}\]
\[1108 < 2236\ :2\]
\[Ответ:число\ 2236.\]