what um

it's like a measurement but the u is all wierd...
I'm trying to convert 462 um to centimers...

anybody can tell me an easier way to convert measurements?

also use the si prefixes to convert these hypthetical units of measure into appropraite quanities

10 rations
2000 mocking birds
10^-6 phones
10^-9 goats
10^18 miners

what exactly am I suppose to do here? Suppose to convert goats and mocking birds? What on Earth am I suppose to do?