\[\boxed{\mathbf{Вариант\ 1.}}\]
\[\boxed{\mathbf{1.}}\]
\[1)\ 3 \cdot 8 = 24\]
\[4 \cdot 6 = 24\]
\[9 \cdot 3 = 27\]
\[7 \cdot 4 = 28\]
\[16\ :4 = 4\]
\[28\ :4 = 7\]
\[21\ :3 = 7\]
\[36\ :9 = 4\]
\[20\ :5 = 4\]
\[4 \cdot 8 = 32\]
\[12\ :6 = 2\]
\[3 \cdot 7 = 21\]
\[2)\ 80 + 24\ :6 = 80 + 4 = 84\]
\[50 - 4 \cdot (12 - 5) = 50 - 28 =\]
\[= 22\]
\[70 - 5 \cdot 4 = 70 - 20 = 50\]
\[\boxed{\mathbf{2.}}\]
\[6 \cdot 3 + 10 = 18 + 10 =\]
\[= 28\ (пирожков) - на\ всех\ \]
\[тарелках.\]
\[Ответ:28\ пирожков.\]
\[\boxed{\mathbf{3.}}\]
\[24\ :6 = 20\ :5\]
\[6 \cdot 3 = 9 \cdot 2\]
\[3 \cdot 8 = 4 \cdot 6\]
\[\boxed{\mathbf{4.}}\]
\[3 \cdot 4\ :2 = 6\]
\[4\ :2 \cdot 8 = 16\]
\[6 \cdot 3\ :2 = 9\]