$$\begin{array}{@{}c@{\,}c@{}c@{}c} & & 1, & 6 \\ & \times & 5, & 1 \\ \hline & & 1 & 6 \\ + & 8 & 0 & \\ \hline & 8, & 1 & 6 \\ \end{array}$$
$$1.6 \cdot 5.1 = 8.16$$