Express $8km850m$ as kilometre $\left(km\right)$ using decimals.

We know that, $1km=1000m$

We are converting the lower unit to the higher unit. So, we will divide the smaller unit to get the bigger unit.

$$\begin{gathered} 8km850m=8km+850m \\ 8km850m=8km+\frac{850}{1000}km \\ 8km850m=8km+0.850km \\ 8km850m=8.850km \end{gathered}$$

Hence, $8km850m=8.850km$.