Yes, conversion between mm, cm, m and km is easy. What's your point? If something is miles away why do I care about it in terms of feet? How many meters is the sun from here? How many km is 1/3 of an AU? How many seconds does it take light to go a meter in vacuum?

A 16th is half an 8th. Twice as much as a 32nd. AKA 2^4, 2^3 and 2^5, respectively.