The $6$th term of $16 + 8 + 4 + 2 + 1 + \cdots$ is —

With $a=16$ and $r=\tfrac12$, the sixth term is $16\left(\tfrac12\right)^{5}=2^{4}\cdot 2^{-5}=2^{-1}=\dfrac{1}{2}$.