Although it is a simple question, but the trick is to save time in solving this.
Rather than multiplying it we can do as follows:
586645 * (10000 - 1) = 5866450000 - 586645 = 5865863355
3. What is the unit digit in
\begin{aligned}
(6324)^{1797} \times (615)^{316} \times (341)^{476}
\end{aligned}
