\[(0,2)^{20} \bullet 5^{21} + 2^{6} \bullet 5^{6}\ :10^{5} =\]
\[= \left( \frac{1}{5} \right)^{20} \bullet \left( \frac{5}{1} \right)^{21} + \frac{(2 \bullet 5)^{6}}{10^{5}} =\]
\[= 5 + 10 = 15\]