\[\boxed{\text{270\ (270).\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[1)\ a^{7} \cdot a^{5} = a^{7 + 5} = a^{12}\]
\[2)\ a^{7}\ :a^{5} = a^{7 - 5} = a^{2}\]
\[3)\ \left( a^{7} \right)^{5} = a^{7 \cdot 5} = a^{35}\]
\[4)\ \frac{\left( a^{3} \right)^{6} \cdot a^{4}}{a^{16}} = \frac{a^{18} \cdot a^{4}}{a^{16}} =\]
\[= \frac{a^{22}}{a^{16}} = a^{6}\ \]
\[\boxed{\text{270.\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[1)\ a^{7} \cdot a^{5} = a^{7 + 5} = a^{12}\]
\[2)\ a^{7}\ :a^{5} = a^{7 - 5} = a^{2}\]
\[3)\ \left( a^{7} \right)^{5} = a^{7 \cdot 5} = a^{35}\]
\[4)\ \frac{\left( a^{3} \right)^{6} \cdot a^{4}}{a^{16}} = \frac{a^{18} \cdot a^{4}}{a^{16}} =\]
\[= \frac{a^{22}}{a^{16}} = a^{6}\ \]