G1.1 Calculate the tens digit of $2011^{2011}$.
$$
\begin{aligned}
2011^{2011} & \equiv(10+1)^{2011} \bmod 10 \\
& \equiv 10^{2011}+\ldots+2011 \times 10+1 \equiv 11 \bmod 10
\end{aligned}
$$

The tens digit is 1 .