$1.2014^{2015}$ 的个位数为

The unit digit of $1.2014^{2015}$ is
-1.4 .
Let $g(n)$ denote the unit digit of a natural number $n$.
$$
\begin{array}{l}
\text { Then } g\left(2014^{2015}\right) \\
=g\left((201 \times 10+4)^{2015}\right) \\
=g\left(4^{2015}\right)=g\left(\left(4^{2}\right)^{1007} \times 4\right) \\
=g\left((10+6)^{1007} \times 4\right)=g\left(6^{1007} \times 4\right) \\
=g\left(g\left(6^{1007}\right) g(4)\right)=g(6 \times 4)=4 .
\end{array}
$$

Therefore, the unit digit of $2014^{2015}$ is 4.