1) There is a practical way to convert those units from the Metric System. We can sketch out a ladder so that it is easier to understand:
2) Since we have 0.1 hectometers to convert into meters let's write in blue, so 0.1 hm = 10 m Notice that we have actually multiplied by 10 and then 10 again.
2.2) Now, let's go all the way up from dm to meters, in red. So 8 dm is equivalent to 0.8m (Actually we have divided by 10)
3) Hence the answer is: