The units digit of $18^6$ is the same as in $8^6$.  There are several ways we could go about finding that units digit, but notice that $8^6 = 2^{18}$.  It's easy to find the pattern of units digits for powers of 2:  \begin{align*} 2^1 &= 2 \\ 2^2 &= 4 \\ 2^3 &= 8 \\ 2^4 &= 16 \\ 2^5 &= 32 \end{align*}Using this pattern, the units digit is found to be $\boxed{4}$.
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Find the units digit of $18^6.$
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
4
Find the units digit of $18^6.$
test